src/chrome/renderer/printing/print_web_view_helper.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/renderer/printing/print_web_view_helper.h"
   6
   7 #include <string>
   8
   9 #include "base/auto_reset.h"
  10 #include "base/command_line.h"
  11 #include "base/json/json_writer.h"
  12 #include "base/logging.h"
  13 #include "base/message_loop/message_loop.h"
  14 #include "base/metrics/histogram.h"
  15 #include "base/process/process_handle.h"
  16 #include "base/strings/string_number_conversions.h"
  17 #include "base/strings/stringprintf.h"
  18 #include "base/strings/utf_string_conversions.h"
  19 #include "chrome/common/chrome_switches.h"
  20 #include "chrome/common/print_messages.h"
  21 #include "chrome/common/render_messages.h"
  22 #include "chrome/grit/browser_resources.h"
  23 #include "chrome/renderer/prerender/prerender_helper.h"
  24 #include "content/public/common/web_preferences.h"
  25 #include "content/public/renderer/render_frame.h"
  26 #include "content/public/renderer/render_thread.h"
  27 #include "content/public/renderer/render_view.h"
  28 #include "net/base/escape.h"
  29 #include "printing/pdf_metafile_skia.h"
  30 #include "printing/units.h"
  31 #include "skia/ext/vector_platform_device_skia.h"
  32 #include "third_party/WebKit/public/platform/WebSize.h"
  33 #include "third_party/WebKit/public/platform/WebURLRequest.h"
  34 #include "third_party/WebKit/public/web/WebConsoleMessage.h"
  35 #include "third_party/WebKit/public/web/WebDocument.h"
  36 #include "third_party/WebKit/public/web/WebElement.h"
  37 #include "third_party/WebKit/public/web/WebFrameClient.h"
  38 #include "third_party/WebKit/public/web/WebLocalFrame.h"
  39 #include "third_party/WebKit/public/web/WebPlugin.h"
  40 #include "third_party/WebKit/public/web/WebPluginDocument.h"
  41 #include "third_party/WebKit/public/web/WebPrintParams.h"
  42 #include "third_party/WebKit/public/web/WebPrintScalingOption.h"
  43 #include "third_party/WebKit/public/web/WebScriptSource.h"
  44 #include "third_party/WebKit/public/web/WebSettings.h"
  45 #include "third_party/WebKit/public/web/WebView.h"
  46 #include "third_party/WebKit/public/web/WebViewClient.h"
  47 #include "ui/base/resource/resource_bundle.h"
  48
  49 using content::WebPreferences;
  50
  51 namespace printing {
  52
  53 namespace {
  54
  55 enum PrintPreviewHelperEvents {
  56   PREVIEW_EVENT_REQUESTED,
  57   PREVIEW_EVENT_CACHE_HIT,  // Unused
  58   PREVIEW_EVENT_CREATE_DOCUMENT,
  59   PREVIEW_EVENT_NEW_SETTINGS,  // Unused
  60   PREVIEW_EVENT_MAX,
  61 };
  62
  63 const double kMinDpi = 1.0;
  64
  65 #if !defined(ENABLE_PRINT_PREVIEW)
  66 bool g_is_preview_enabled_ = false;
  67 #else
  68 bool g_is_preview_enabled_ = true;
  69
  70 const char kPageLoadScriptFormat[] =
  71     "document.open(); document.write(%s); document.close();";
  72
  73 const char kPageSetupScriptFormat[] = "setup(%s);";
  74
  75 void ExecuteScript(blink::WebFrame* frame,
  76                    const char* script_format,
  77                    const base::Value& parameters) {
  78   std::string json;
  79   base::JSONWriter::Write(&parameters, &json);
  80   std::string script = base::StringPrintf(script_format, json.c_str());
  81   frame->executeScript(blink::WebString(base::UTF8ToUTF16(script)));
  82 }
  83 #endif  // !defined(ENABLE_PRINT_PREVIEW)
  84
  85 int GetDPI(const PrintMsg_Print_Params* print_params) {
  86 #if defined(OS_MACOSX)
  87   // On the Mac, the printable area is in points, don't do any scaling based
  88   // on dpi.
  89   return kPointsPerInch;
  90 #else
  91   return static_cast<int>(print_params->dpi);
  92 #endif  // defined(OS_MACOSX)
  93 }
  94
  95 bool PrintMsg_Print_Params_IsValid(const PrintMsg_Print_Params& params) {
  96   return !params.content_size.IsEmpty() && !params.page_size.IsEmpty() &&
  97          !params.printable_area.IsEmpty() && params.document_cookie &&
  98          params.desired_dpi && params.max_shrink && params.min_shrink &&
  99          params.dpi && (params.margin_top >= 0) && (params.margin_left >= 0) &&
 100          params.dpi > kMinDpi && params.document_cookie != 0;
 101 }
 102
 103 PrintMsg_Print_Params GetCssPrintParams(
 104     blink::WebFrame* frame,
 105     int page_index,
 106     const PrintMsg_Print_Params& page_params) {
 107   PrintMsg_Print_Params page_css_params = page_params;
 108   int dpi = GetDPI(&page_params);
 109
 110   blink::WebSize page_size_in_pixels(
 111       ConvertUnit(page_params.page_size.width(), dpi, kPixelsPerInch),
 112       ConvertUnit(page_params.page_size.height(), dpi, kPixelsPerInch));
 113   int margin_top_in_pixels =
 114       ConvertUnit(page_params.margin_top, dpi, kPixelsPerInch);
 115   int margin_right_in_pixels = ConvertUnit(
 116       page_params.page_size.width() -
 117       page_params.content_size.width() - page_params.margin_left,
 118       dpi, kPixelsPerInch);
 119   int margin_bottom_in_pixels = ConvertUnit(
 120       page_params.page_size.height() -
 121       page_params.content_size.height() - page_params.margin_top,
 122       dpi, kPixelsPerInch);
 123   int margin_left_in_pixels = ConvertUnit(
 124       page_params.margin_left,
 125       dpi, kPixelsPerInch);
 126
 127   blink::WebSize original_page_size_in_pixels = page_size_in_pixels;
 128
 129   if (frame) {
 130     frame->pageSizeAndMarginsInPixels(page_index,
 131                                       page_size_in_pixels,
 132                                       margin_top_in_pixels,
 133                                       margin_right_in_pixels,
 134                                       margin_bottom_in_pixels,
 135                                       margin_left_in_pixels);
 136   }
 137
 138   int new_content_width = page_size_in_pixels.width -
 139                           margin_left_in_pixels - margin_right_in_pixels;
 140   int new_content_height = page_size_in_pixels.height -
 141                            margin_top_in_pixels - margin_bottom_in_pixels;
 142
 143   // Invalid page size and/or margins. We just use the default setting.
 144   if (new_content_width < 1 || new_content_height < 1) {
 145     CHECK(frame != NULL);
 146     page_css_params = GetCssPrintParams(NULL, page_index, page_params);
 147     return page_css_params;
 148   }
 149
 150   page_css_params.content_size = gfx::Size(
 151       ConvertUnit(new_content_width, kPixelsPerInch, dpi),
 152       ConvertUnit(new_content_height, kPixelsPerInch, dpi));
 153
 154   if (original_page_size_in_pixels != page_size_in_pixels) {
 155     page_css_params.page_size = gfx::Size(
 156         ConvertUnit(page_size_in_pixels.width, kPixelsPerInch, dpi),
 157         ConvertUnit(page_size_in_pixels.height, kPixelsPerInch, dpi));
 158   } else {
 159     // Printing frame doesn't have any page size css. Pixels to dpi conversion
 160     // causes rounding off errors. Therefore use the default page size values
 161     // directly.
 162     page_css_params.page_size = page_params.page_size;
 163   }
 164
 165   page_css_params.margin_top =
 166       ConvertUnit(margin_top_in_pixels, kPixelsPerInch, dpi);
 167   page_css_params.margin_left =
 168       ConvertUnit(margin_left_in_pixels, kPixelsPerInch, dpi);
 169   return page_css_params;
 170 }
 171
 172 double FitPrintParamsToPage(const PrintMsg_Print_Params& page_params,
 173                             PrintMsg_Print_Params* params_to_fit) {
 174   double content_width =
 175       static_cast<double>(params_to_fit->content_size.width());
 176   double content_height =
 177       static_cast<double>(params_to_fit->content_size.height());
 178   int default_page_size_height = page_params.page_size.height();
 179   int default_page_size_width = page_params.page_size.width();
 180   int css_page_size_height = params_to_fit->page_size.height();
 181   int css_page_size_width = params_to_fit->page_size.width();
 182
 183   double scale_factor = 1.0f;
 184   if (page_params.page_size == params_to_fit->page_size)
 185     return scale_factor;
 186
 187   if (default_page_size_width < css_page_size_width ||
 188       default_page_size_height < css_page_size_height) {
 189     double ratio_width =
 190         static_cast<double>(default_page_size_width) / css_page_size_width;
 191     double ratio_height =
 192         static_cast<double>(default_page_size_height) / css_page_size_height;
 193     scale_factor = ratio_width < ratio_height ? ratio_width : ratio_height;
 194     content_width *= scale_factor;
 195     content_height *= scale_factor;
 196   }
 197   params_to_fit->margin_top = static_cast<int>(
 198       (default_page_size_height - css_page_size_height * scale_factor) / 2 +
 199       (params_to_fit->margin_top * scale_factor));
 200   params_to_fit->margin_left = static_cast<int>(
 201       (default_page_size_width - css_page_size_width * scale_factor) / 2 +
 202       (params_to_fit->margin_left * scale_factor));
 203   params_to_fit->content_size = gfx::Size(
 204       static_cast<int>(content_width), static_cast<int>(content_height));
 205   params_to_fit->page_size = page_params.page_size;
 206   return scale_factor;
 207 }
 208
 209 void CalculatePageLayoutFromPrintParams(
 210     const PrintMsg_Print_Params& params,
 211     PageSizeMargins* page_layout_in_points) {
 212   int dpi = GetDPI(&params);
 213   int content_width = params.content_size.width();
 214   int content_height = params.content_size.height();
 215
 216   int margin_bottom = params.page_size.height() -
 217                       content_height - params.margin_top;
 218   int margin_right = params.page_size.width() -
 219                       content_width - params.margin_left;
 220
 221   page_layout_in_points->content_width =
 222       ConvertUnit(content_width, dpi, kPointsPerInch);
 223   page_layout_in_points->content_height =
 224       ConvertUnit(content_height, dpi, kPointsPerInch);
 225   page_layout_in_points->margin_top =
 226       ConvertUnit(params.margin_top, dpi, kPointsPerInch);
 227   page_layout_in_points->margin_right =
 228       ConvertUnit(margin_right, dpi, kPointsPerInch);
 229   page_layout_in_points->margin_bottom =
 230       ConvertUnit(margin_bottom, dpi, kPointsPerInch);
 231   page_layout_in_points->margin_left =
 232       ConvertUnit(params.margin_left, dpi, kPointsPerInch);
 233 }
 234
 235 void EnsureOrientationMatches(const PrintMsg_Print_Params& css_params,
 236                               PrintMsg_Print_Params* page_params) {
 237   if ((page_params->page_size.width() > page_params->page_size.height()) ==
 238       (css_params.page_size.width() > css_params.page_size.height())) {
 239     return;
 240   }
 241
 242   // Swap the |width| and |height| values.
 243   page_params->page_size.SetSize(page_params->page_size.height(),
 244                                  page_params->page_size.width());
 245   page_params->content_size.SetSize(page_params->content_size.height(),
 246                                     page_params->content_size.width());
 247   page_params->printable_area.set_size(
 248       gfx::Size(page_params->printable_area.height(),
 249                 page_params->printable_area.width()));
 250 }
 251
 252 void ComputeWebKitPrintParamsInDesiredDpi(
 253     const PrintMsg_Print_Params& print_params,
 254     blink::WebPrintParams* webkit_print_params) {
 255   int dpi = GetDPI(&print_params);
 256   webkit_print_params->printerDPI = dpi;
 257   webkit_print_params->printScalingOption = print_params.print_scaling_option;
 258
 259   webkit_print_params->printContentArea.width =
 260       ConvertUnit(print_params.content_size.width(), dpi,
 261                   print_params.desired_dpi);
 262   webkit_print_params->printContentArea.height =
 263       ConvertUnit(print_params.content_size.height(), dpi,
 264                   print_params.desired_dpi);
 265
 266   webkit_print_params->printableArea.x =
 267       ConvertUnit(print_params.printable_area.x(), dpi,
 268                   print_params.desired_dpi);
 269   webkit_print_params->printableArea.y =
 270       ConvertUnit(print_params.printable_area.y(), dpi,
 271                   print_params.desired_dpi);
 272   webkit_print_params->printableArea.width =
 273       ConvertUnit(print_params.printable_area.width(), dpi,
 274                   print_params.desired_dpi);
 275   webkit_print_params->printableArea.height =
 276       ConvertUnit(print_params.printable_area.height(),
 277                   dpi, print_params.desired_dpi);
 278
 279   webkit_print_params->paperSize.width =
 280       ConvertUnit(print_params.page_size.width(), dpi,
 281                   print_params.desired_dpi);
 282   webkit_print_params->paperSize.height =
 283       ConvertUnit(print_params.page_size.height(), dpi,
 284                   print_params.desired_dpi);
 285 }
 286
 287 blink::WebPlugin* GetPlugin(const blink::WebFrame* frame) {
 288   return frame->document().isPluginDocument() ?
 289          frame->document().to<blink::WebPluginDocument>().plugin() : NULL;
 290 }
 291
 292 bool PrintingNodeOrPdfFrame(const blink::WebFrame* frame,
 293                             const blink::WebNode& node) {
 294   if (!node.isNull())
 295     return true;
 296   blink::WebPlugin* plugin = GetPlugin(frame);
 297   return plugin && plugin->supportsPaginatedPrint();
 298 }
 299
 300 bool PrintingFrameHasPageSizeStyle(blink::WebFrame* frame,
 301                                    int total_page_count) {
 302   if (!frame)
 303     return false;
 304   bool frame_has_custom_page_size_style = false;
 305   for (int i = 0; i < total_page_count; ++i) {
 306     if (frame->hasCustomPageSizeStyle(i)) {
 307       frame_has_custom_page_size_style = true;
 308       break;
 309     }
 310   }
 311   return frame_has_custom_page_size_style;
 312 }
 313
 314 MarginType GetMarginsForPdf(blink::WebFrame* frame,
 315                             const blink::WebNode& node) {
 316   if (frame->isPrintScalingDisabledForPlugin(node))
 317     return NO_MARGINS;
 318   else
 319     return PRINTABLE_AREA_MARGINS;
 320 }
 321
 322 bool FitToPageEnabled(const base::DictionaryValue& job_settings) {
 323   bool fit_to_paper_size = false;
 324   if (!job_settings.GetBoolean(kSettingFitToPageEnabled, &fit_to_paper_size)) {
 325     NOTREACHED();
 326   }
 327   return fit_to_paper_size;
 328 }
 329
 330 // Returns the print scaling option to retain/scale/crop the source page size
 331 // to fit the printable area of the paper.
 332 //
 333 // We retain the source page size when the current destination printer is
 334 // SAVE_AS_PDF.
 335 //
 336 // We crop the source page size to fit the printable area or we print only the
 337 // left top page contents when
 338 // (1) Source is PDF and the user has requested not to fit to printable area
 339 // via |job_settings|.
 340 // (2) Source is PDF. This is the first preview request and print scaling
 341 // option is disabled for initiator renderer plugin.
 342 //
 343 // In all other cases, we scale the source page to fit the printable area.
 344 blink::WebPrintScalingOption GetPrintScalingOption(
 345     blink::WebFrame* frame,
 346     const blink::WebNode& node,
 347     bool source_is_html,
 348     const base::DictionaryValue& job_settings,
 349     const PrintMsg_Print_Params& params) {
 350   if (params.print_to_pdf)
 351     return blink::WebPrintScalingOptionSourceSize;
 352
 353   if (!source_is_html) {
 354     if (!FitToPageEnabled(job_settings))
 355       return blink::WebPrintScalingOptionNone;
 356
 357     bool no_plugin_scaling = frame->isPrintScalingDisabledForPlugin(node);
 358
 359     if (params.is_first_request && no_plugin_scaling)
 360       return blink::WebPrintScalingOptionNone;
 361   }
 362   return blink::WebPrintScalingOptionFitToPrintableArea;
 363 }
 364
 365 PrintMsg_Print_Params CalculatePrintParamsForCss(
 366     blink::WebFrame* frame,
 367     int page_index,
 368     const PrintMsg_Print_Params& page_params,
 369     bool ignore_css_margins,
 370     bool fit_to_page,
 371     double* scale_factor) {
 372   PrintMsg_Print_Params css_params = GetCssPrintParams(frame, page_index,
 373                                                        page_params);
 374
 375   PrintMsg_Print_Params params = page_params;
 376   EnsureOrientationMatches(css_params, &params);
 377
 378   if (ignore_css_margins && fit_to_page)
 379     return params;
 380
 381   PrintMsg_Print_Params result_params = css_params;
 382   if (ignore_css_margins) {
 383     result_params.margin_top = params.margin_top;
 384     result_params.margin_left = params.margin_left;
 385
 386     DCHECK(!fit_to_page);
 387     // Since we are ignoring the margins, the css page size is no longer
 388     // valid.
 389     int default_margin_right = params.page_size.width() -
 390         params.content_size.width() - params.margin_left;
 391     int default_margin_bottom = params.page_size.height() -
 392         params.content_size.height() - params.margin_top;
 393     result_params.content_size = gfx::Size(
 394         result_params.page_size.width() - result_params.margin_left -
 395             default_margin_right,
 396         result_params.page_size.height() - result_params.margin_top -
 397             default_margin_bottom);
 398   }
 399
 400   if (fit_to_page) {
 401     double factor = FitPrintParamsToPage(params, &result_params);
 402     if (scale_factor)
 403       *scale_factor = factor;
 404   }
 405   return result_params;
 406 }
 407
 408 }  // namespace
 409
 410 FrameReference::FrameReference(blink::WebLocalFrame* frame) {
 411   Reset(frame);
 412 }
 413
 414 FrameReference::FrameReference() {
 415   Reset(NULL);
 416 }
 417
 418 FrameReference::~FrameReference() {
 419 }
 420
 421 void FrameReference::Reset(blink::WebLocalFrame* frame) {
 422   if (frame) {
 423     view_ = frame->view();
 424     frame_ = frame;
 425   } else {
 426     view_ = NULL;
 427     frame_ = NULL;
 428   }
 429 }
 430
 431 blink::WebLocalFrame* FrameReference::GetFrame() {
 432   if (view_ == NULL || frame_ == NULL)
 433     return NULL;
 434   for (blink::WebFrame* frame = view_->mainFrame(); frame != NULL;
 435            frame = frame->traverseNext(false)) {
 436     if (frame == frame_)
 437       return frame_;
 438   }
 439   return NULL;
 440 }
 441
 442 blink::WebView* FrameReference::view() {
 443   return view_;
 444 }
 445
 446 #if defined(ENABLE_PRINT_PREVIEW)
 447 // static - Not anonymous so that platform implementations can use it.
 448 void PrintWebViewHelper::PrintHeaderAndFooter(
 449     blink::WebCanvas* canvas,
 450     int page_number,
 451     int total_pages,
 452     const blink::WebFrame& source_frame,
 453     float webkit_scale_factor,
 454     const PageSizeMargins& page_layout,
 455     const PrintMsg_Print_Params& params) {
 456   skia::VectorPlatformDeviceSkia* device =
 457       static_cast<skia::VectorPlatformDeviceSkia*>(canvas->getTopDevice());
 458   device->setDrawingArea(SkPDFDevice::kMargin_DrawingArea);
 459
 460   SkAutoCanvasRestore auto_restore(canvas, true);
 461   canvas->scale(1 / webkit_scale_factor, 1 / webkit_scale_factor);
 462
 463   blink::WebSize page_size(page_layout.margin_left + page_layout.margin_right +
 464                                page_layout.content_width,
 465                            page_layout.margin_top + page_layout.margin_bottom +
 466                                page_layout.content_height);
 467
 468   blink::WebView* web_view = blink::WebView::create(NULL);
 469   web_view->settings()->setJavaScriptEnabled(true);
 470
 471   blink::WebLocalFrame* frame = blink::WebLocalFrame::create(NULL);
 472   web_view->setMainFrame(frame);
 473
 474   base::StringValue html(ResourceBundle::GetSharedInstance().GetLocalizedString(
 475       IDR_PRINT_PREVIEW_PAGE));
 476   // Load page with script to avoid async operations.
 477   ExecuteScript(frame, kPageLoadScriptFormat, html);
 478
 479   scoped_ptr<base::DictionaryValue> options(new base::DictionaryValue());
 480   options.reset(new base::DictionaryValue());
 481   options->SetDouble(kSettingHeaderFooterDate, base::Time::Now().ToJsTime());
 482   options->SetDouble("width", page_size.width);
 483   options->SetDouble("height", page_size.height);
 484   options->SetDouble("topMargin", page_layout.margin_top);
 485   options->SetDouble("bottomMargin", page_layout.margin_bottom);
 486   options->SetString("pageNumber",
 487                      base::StringPrintf("%d/%d", page_number, total_pages));
 488
 489   // Fallback to initiator URL and title if it's empty for printed frame.
 490   base::string16 url = source_frame.document().url().string();
 491   options->SetString("url", url.empty() ? params.url : url);
 492   base::string16 title = source_frame.document().title();
 493   options->SetString("title", title.empty() ? params.title : title);
 494
 495   ExecuteScript(frame, kPageSetupScriptFormat, *options);
 496
 497   blink::WebPrintParams webkit_params(page_size);
 498   webkit_params.printerDPI = GetDPI(&params);
 499
 500   frame->printBegin(webkit_params);
 501   frame->printPage(0, canvas);
 502   frame->printEnd();
 503
 504   web_view->close();
 505   frame->close();
 506
 507   device->setDrawingArea(SkPDFDevice::kContent_DrawingArea);
 508 }
 509 #endif  // defined(ENABLE_PRINT_PREVIEW)
 510
 511 // static - Not anonymous so that platform implementations can use it.
 512 float PrintWebViewHelper::RenderPageContent(blink::WebFrame* frame,
 513                                             int page_number,
 514                                             const gfx::Rect& canvas_area,
 515                                             const gfx::Rect& content_area,
 516                                             double scale_factor,
 517                                             blink::WebCanvas* canvas) {
 518   SkAutoCanvasRestore auto_restore(canvas, true);
 519   if (content_area != canvas_area) {
 520     canvas->translate((content_area.x() - canvas_area.x()) / scale_factor,
 521                       (content_area.y() - canvas_area.y()) / scale_factor);
 522     SkRect clip_rect(
 523         SkRect::MakeXYWH(content_area.origin().x() / scale_factor,
 524                          content_area.origin().y() / scale_factor,
 525                          content_area.size().width() / scale_factor,
 526                          content_area.size().height() / scale_factor));
 527     SkIRect clip_int_rect;
 528     clip_rect.roundOut(&clip_int_rect);
 529     SkRegion clip_region(clip_int_rect);
 530     canvas->setClipRegion(clip_region);
 531   }
 532   return frame->printPage(page_number, canvas);
 533 }
 534
 535 // Class that calls the Begin and End print functions on the frame and changes
 536 // the size of the view temporarily to support full page printing..
 537 class PrepareFrameAndViewForPrint : public blink::WebViewClient,
 538                                     public blink::WebFrameClient {
 539  public:
 540   PrepareFrameAndViewForPrint(const PrintMsg_Print_Params& params,
 541                               blink::WebLocalFrame* frame,
 542                               const blink::WebNode& node,
 543                               bool ignore_css_margins);
 544   virtual ~PrepareFrameAndViewForPrint();
 545
 546   // Optional. Replaces |frame_| with selection if needed. Will call |on_ready|
 547   // when completed.
 548   void CopySelectionIfNeeded(const WebPreferences& preferences,
 549                              const base::Closure& on_ready);
 550
 551   // Prepares frame for printing.
 552   void StartPrinting();
 553
 554   blink::WebLocalFrame* frame() {
 555     return frame_.GetFrame();
 556   }
 557
 558   const blink::WebNode& node() const {
 559     return node_to_print_;
 560   }
 561
 562   int GetExpectedPageCount() const {
 563     return expected_pages_count_;
 564   }
 565
 566   void FinishPrinting();
 567
 568   bool IsLoadingSelection() {
 569     // It's not selection if not |owns_web_view_|.
 570     return owns_web_view_ && frame() && frame()->isLoading();
 571   }
 572
 573   // TODO(ojan): Remove this override and have this class use a non-null
 574   // layerTreeView.
 575   // blink::WebViewClient override:
 576   virtual bool allowsBrokenNullLayerTreeView() const;
 577
 578  protected:
 579   // blink::WebViewClient override:
 580   virtual void didStopLoading();
 581
 582   // blink::WebFrameClient override:
 583   virtual blink::WebFrame* createChildFrame(blink::WebLocalFrame* parent,
 584                                             const blink::WebString& name);
 585   virtual void frameDetached(blink::WebFrame* frame);
 586
 587  private:
 588   void CallOnReady();
 589   void ResizeForPrinting();
 590   void RestoreSize();
 591   void CopySelection(const WebPreferences& preferences);
 592
 593   base::WeakPtrFactory<PrepareFrameAndViewForPrint> weak_ptr_factory_;
 594
 595   FrameReference frame_;
 596   blink::WebNode node_to_print_;
 597   bool owns_web_view_;
 598   blink::WebPrintParams web_print_params_;
 599   gfx::Size prev_view_size_;
 600   gfx::Size prev_scroll_offset_;
 601   int expected_pages_count_;
 602   base::Closure on_ready_;
 603   bool should_print_backgrounds_;
 604   bool should_print_selection_only_;
 605   bool is_printing_started_;
 606
 607   DISALLOW_COPY_AND_ASSIGN(PrepareFrameAndViewForPrint);
 608 };
 609
 610 PrepareFrameAndViewForPrint::PrepareFrameAndViewForPrint(
 611     const PrintMsg_Print_Params& params,
 612     blink::WebLocalFrame* frame,
 613     const blink::WebNode& node,
 614     bool ignore_css_margins)
 615     : weak_ptr_factory_(this),
 616       frame_(frame),
 617       node_to_print_(node),
 618       owns_web_view_(false),
 619       expected_pages_count_(0),
 620       should_print_backgrounds_(params.should_print_backgrounds),
 621       should_print_selection_only_(params.selection_only),
 622       is_printing_started_(false) {
 623   PrintMsg_Print_Params print_params = params;
 624   if (!should_print_selection_only_ ||
 625       !PrintingNodeOrPdfFrame(frame, node_to_print_)) {
 626     bool fit_to_page = ignore_css_margins &&
 627                        print_params.print_scaling_option ==
 628                             blink::WebPrintScalingOptionFitToPrintableArea;
 629     ComputeWebKitPrintParamsInDesiredDpi(params, &web_print_params_);
 630     frame->printBegin(web_print_params_, node_to_print_);
 631     print_params = CalculatePrintParamsForCss(frame, 0, print_params,
 632                                               ignore_css_margins, fit_to_page,
 633                                               NULL);
 634     frame->printEnd();
 635   }
 636   ComputeWebKitPrintParamsInDesiredDpi(print_params, &web_print_params_);
 637 }
 638
 639 PrepareFrameAndViewForPrint::~PrepareFrameAndViewForPrint() {
 640   FinishPrinting();
 641 }
 642
 643 void PrepareFrameAndViewForPrint::ResizeForPrinting() {
 644   // Layout page according to printer page size. Since WebKit shrinks the
 645   // size of the page automatically (from 125% to 200%) we trick it to
 646   // think the page is 125% larger so the size of the page is correct for
 647   // minimum (default) scaling.
 648   // This is important for sites that try to fill the page.
 649   gfx::Size print_layout_size(web_print_params_.printContentArea.width,
 650                               web_print_params_.printContentArea.height);
 651   print_layout_size.set_height(
 652       static_cast<int>(static_cast<double>(print_layout_size.height()) * 1.25));
 653
 654   if (!frame())
 655     return;
 656   blink::WebView* web_view = frame_.view();
 657   // Backup size and offset.
 658   if (blink::WebFrame* web_frame = web_view->mainFrame())
 659     prev_scroll_offset_ = web_frame->scrollOffset();
 660   prev_view_size_ = web_view->size();
 661
 662   web_view->resize(print_layout_size);
 663 }
 664
 665
 666 void PrepareFrameAndViewForPrint::StartPrinting() {
 667   ResizeForPrinting();
 668   blink::WebView* web_view = frame_.view();
 669   web_view->settings()->setShouldPrintBackgrounds(should_print_backgrounds_);
 670   expected_pages_count_ =
 671       frame()->printBegin(web_print_params_, node_to_print_);
 672   is_printing_started_ = true;
 673 }
 674
 675 void PrepareFrameAndViewForPrint::CopySelectionIfNeeded(
 676     const WebPreferences& preferences,
 677     const base::Closure& on_ready) {
 678   on_ready_ = on_ready;
 679   if (should_print_selection_only_) {
 680     CopySelection(preferences);
 681   } else {
 682     // Call immediately, async call crashes scripting printing.
 683     CallOnReady();
 684   }
 685 }
 686
 687 void PrepareFrameAndViewForPrint::CopySelection(
 688     const WebPreferences& preferences) {
 689   ResizeForPrinting();
 690   std::string url_str = "data:text/html;charset=utf-8,";
 691   url_str.append(
 692       net::EscapeQueryParamValue(frame()->selectionAsMarkup().utf8(), false));
 693   RestoreSize();
 694   // Create a new WebView with the same settings as the current display one.
 695   // Except that we disable javascript (don't want any active content running
 696   // on the page).
 697   WebPreferences prefs = preferences;
 698   prefs.javascript_enabled = false;
 699   prefs.java_enabled = false;
 700
 701   blink::WebView* web_view = blink::WebView::create(this);
 702   owns_web_view_ = true;
 703   content::RenderView::ApplyWebPreferences(prefs, web_view);
 704   web_view->setMainFrame(blink::WebLocalFrame::create(this));
 705   frame_.Reset(web_view->mainFrame()->toWebLocalFrame());
 706   node_to_print_.reset();
 707
 708   // When loading is done this will call didStopLoading() and that will do the
 709   // actual printing.
 710   frame()->loadRequest(blink::WebURLRequest(GURL(url_str)));
 711 }
 712
 713 bool PrepareFrameAndViewForPrint::allowsBrokenNullLayerTreeView() const {
 714   return true;
 715 }
 716
 717 void PrepareFrameAndViewForPrint::didStopLoading() {
 718   DCHECK(!on_ready_.is_null());
 719   // Don't call callback here, because it can delete |this| and WebView that is
 720   // called didStopLoading.
 721   base::MessageLoop::current()->PostTask(
 722       FROM_HERE,
 723       base::Bind(&PrepareFrameAndViewForPrint::CallOnReady,
 724                  weak_ptr_factory_.GetWeakPtr()));
 725 }
 726
 727 blink::WebFrame* PrepareFrameAndViewForPrint::createChildFrame(
 728     blink::WebLocalFrame* parent,
 729     const blink::WebString& name) {
 730   blink::WebFrame* frame = blink::WebLocalFrame::create(this);
 731   parent->appendChild(frame);
 732   return frame;
 733 }
 734
 735 void PrepareFrameAndViewForPrint::frameDetached(blink::WebFrame* frame) {
 736   if (frame->parent())
 737     frame->parent()->removeChild(frame);
 738   frame->close();
 739 }
 740
 741 void PrepareFrameAndViewForPrint::CallOnReady() {
 742   return on_ready_.Run();  // Can delete |this|.
 743 }
 744
 745 void PrepareFrameAndViewForPrint::RestoreSize() {
 746   if (frame()) {
 747     blink::WebView* web_view = frame_.GetFrame()->view();
 748     web_view->resize(prev_view_size_);
 749     if (blink::WebFrame* web_frame = web_view->mainFrame())
 750       web_frame->setScrollOffset(prev_scroll_offset_);
 751   }
 752 }
 753
 754 void PrepareFrameAndViewForPrint::FinishPrinting() {
 755   blink::WebLocalFrame* frame = frame_.GetFrame();
 756   if (frame) {
 757     blink::WebView* web_view = frame->view();
 758     if (is_printing_started_) {
 759       is_printing_started_ = false;
 760       frame->printEnd();
 761       if (!owns_web_view_) {
 762         web_view->settings()->setShouldPrintBackgrounds(false);
 763         RestoreSize();
 764       }
 765     }
 766     if (owns_web_view_) {
 767       DCHECK(!frame->isLoading());
 768       owns_web_view_ = false;
 769       web_view->close();
 770     }
 771   }
 772   frame_.Reset(NULL);
 773   on_ready_.Reset();
 774 }
 775
 776 PrintWebViewHelper::PrintWebViewHelper(content::RenderView* render_view)
 777     : content::RenderViewObserver(render_view),
 778       content::RenderViewObserverTracker<PrintWebViewHelper>(render_view),
 779       reset_prep_frame_view_(false),
 780       is_print_ready_metafile_sent_(false),
 781       ignore_css_margins_(false),
 782       is_scripted_printing_blocked_(false),
 783       notify_browser_of_print_failure_(true),
 784       print_for_preview_(false),
 785       print_node_in_progress_(false),
 786       is_loading_(false),
 787       is_scripted_preview_delayed_(false),
 788       weak_ptr_factory_(this) {
 789   if (CommandLine::ForCurrentProcess()->HasSwitch(
 790           switches::kDisablePrintPreview)) {
 791     DisablePreview();
 792   }
 793 }
 794
 795 PrintWebViewHelper::~PrintWebViewHelper() {}
 796
 797 // static
 798 void PrintWebViewHelper::DisablePreview() {
 799   g_is_preview_enabled_ = false;
 800 }
 801
 802 bool PrintWebViewHelper::IsScriptInitiatedPrintAllowed(
 803     blink::WebFrame* frame, bool user_initiated) {
 804 #if defined(OS_ANDROID)
 805   return false;
 806 #endif  // defined(OS_ANDROID)
 807   // If preview is enabled, then the print dialog is tab modal, and the user
 808   // can always close the tab on a mis-behaving page (the system print dialog
 809   // is app modal). If the print was initiated through user action, don't
 810   // throttle. Or, if the command line flag to skip throttling has been set.
 811   return !is_scripted_printing_blocked_ &&
 812          (user_initiated || g_is_preview_enabled_ ||
 813           scripting_throttler_.IsAllowed(frame));
 814 }
 815
 816 void PrintWebViewHelper::DidStartLoading() {
 817   is_loading_ = true;
 818 }
 819
 820 void PrintWebViewHelper::DidStopLoading() {
 821   is_loading_ = false;
 822   if (!on_stop_loading_closure_.is_null()) {
 823     on_stop_loading_closure_.Run();
 824     on_stop_loading_closure_.Reset();
 825   }
 826 }
 827
 828 // Prints |frame| which called window.print().
 829 void PrintWebViewHelper::PrintPage(blink::WebLocalFrame* frame,
 830                                    bool user_initiated) {
 831   DCHECK(frame);
 832
 833   // Allow Prerendering to cancel this print request if necessary.
 834   if (prerender::PrerenderHelper::IsPrerendering(
 835           render_view()->GetMainRenderFrame())) {
 836     Send(new ChromeViewHostMsg_CancelPrerenderForPrinting(routing_id()));
 837     return;
 838   }
 839
 840   if (!IsScriptInitiatedPrintAllowed(frame, user_initiated))
 841     return;
 842
 843   if (!g_is_preview_enabled_) {
 844     Print(frame, blink::WebNode());
 845   } else {
 846     print_preview_context_.InitWithFrame(frame);
 847     RequestPrintPreview(PRINT_PREVIEW_SCRIPTED);
 848   }
 849 }
 850
 851 bool PrintWebViewHelper::OnMessageReceived(const IPC::Message& message) {
 852   bool handled = true;
 853   IPC_BEGIN_MESSAGE_MAP(PrintWebViewHelper, message)
 854 #if defined(ENABLE_BASIC_PRINTING)
 855     IPC_MESSAGE_HANDLER(PrintMsg_PrintPages, OnPrintPages)
 856     IPC_MESSAGE_HANDLER(PrintMsg_PrintForSystemDialog, OnPrintForSystemDialog)
 857 #endif  // ENABLE_BASIC_PRINTING
 858     IPC_MESSAGE_HANDLER(PrintMsg_InitiatePrintPreview, OnInitiatePrintPreview)
 859     IPC_MESSAGE_HANDLER(PrintMsg_PrintPreview, OnPrintPreview)
 860     IPC_MESSAGE_HANDLER(PrintMsg_PrintForPrintPreview, OnPrintForPrintPreview)
 861     IPC_MESSAGE_HANDLER(PrintMsg_PrintingDone, OnPrintingDone)
 862     IPC_MESSAGE_HANDLER(PrintMsg_SetScriptedPrintingBlocked,
 863                         SetScriptedPrintBlocked)
 864     IPC_MESSAGE_UNHANDLED(handled = false)
 865     IPC_END_MESSAGE_MAP()
 866   return handled;
 867 }
 868
 869 void PrintWebViewHelper::OnPrintForPrintPreview(
 870     const base::DictionaryValue& job_settings) {
 871   // If still not finished with earlier print request simply ignore.
 872   if (prep_frame_view_)
 873     return;
 874
 875   if (!render_view()->GetWebView())
 876     return;
 877   blink::WebFrame* main_frame = render_view()->GetWebView()->mainFrame();
 878   if (!main_frame)
 879     return;
 880
 881   blink::WebDocument document = main_frame->document();
 882   // <object>/<iframe> with id="pdf-viewer" is created in
 883   // chrome/browser/resources/print_preview/print_preview.js
 884   blink::WebElement pdf_element = document.getElementById("pdf-viewer");
 885   if (pdf_element.isNull()) {
 886     NOTREACHED();
 887     return;
 888   }
 889
 890   // The out-of-process plugin element is nested within a frame.
 891   blink::WebLocalFrame* plugin_frame = pdf_element.document().frame();
 892   blink::WebElement plugin_element = pdf_element;
 893   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kOutOfProcessPdf)) {
 894     if (!pdf_element.hasHTMLTagName("iframe")) {
 895       NOTREACHED();
 896       return;
 897     }
 898     plugin_frame = blink::WebLocalFrame::fromFrameOwnerElement(pdf_element);
 899     // <object> with id="plugin" is created in
 900     // chrome/browser/resources/pdf/pdf.js.
 901     plugin_element = plugin_frame->document().getElementById("plugin");
 902     if (plugin_element.isNull()) {
 903       NOTREACHED();
 904       return;
 905     }
 906   }
 907
 908   // Set |print_for_preview_| flag and autoreset it to back to original
 909   // on return.
 910   base::AutoReset<bool> set_printing_flag(&print_for_preview_, true);
 911
 912   if (!UpdatePrintSettings(plugin_frame, plugin_element, job_settings)) {
 913     LOG(ERROR) << "UpdatePrintSettings failed";
 914     DidFinishPrinting(FAIL_PRINT);
 915     return;
 916   }
 917
 918   // Print page onto entire page not just printable area. Preview PDF already
 919   // has content in correct position taking into account page size and printable
 920   // area.
 921   // TODO(vitalybuka) : Make this consistent on all platform. This change
 922   // affects Windows only. On Linux and OSX RenderPagesForPrint does not use
 923   // printable_area. Also we can't change printable_area deeper inside
 924   // RenderPagesForPrint for Windows, because it's used also by native
 925   // printing and it expects real printable_area value.
 926   // See http://crbug.com/123408
 927   PrintMsg_Print_Params& print_params = print_pages_params_->params;
 928   print_params.printable_area = gfx::Rect(print_params.page_size);
 929
 930   // Render Pages for printing.
 931   if (!RenderPagesForPrint(plugin_frame, plugin_element)) {
 932     LOG(ERROR) << "RenderPagesForPrint failed";
 933     DidFinishPrinting(FAIL_PRINT);
 934   }
 935 }
 936
 937 bool PrintWebViewHelper::GetPrintFrame(blink::WebLocalFrame** frame) {
 938   DCHECK(frame);
 939   blink::WebView* webView = render_view()->GetWebView();
 940   DCHECK(webView);
 941   if (!webView)
 942     return false;
 943
 944   // If the user has selected text in the currently focused frame we print
 945   // only that frame (this makes print selection work for multiple frames).
 946   blink::WebLocalFrame* focusedFrame =
 947       webView->focusedFrame()->toWebLocalFrame();
 948   *frame = focusedFrame->hasSelection()
 949                ? focusedFrame
 950                : webView->mainFrame()->toWebLocalFrame();
 951   return true;
 952 }
 953
 954 #if defined(ENABLE_BASIC_PRINTING)
 955 void PrintWebViewHelper::OnPrintPages() {
 956   blink::WebLocalFrame* frame;
 957   if (GetPrintFrame(&frame))
 958     Print(frame, blink::WebNode());
 959 }
 960
 961 void PrintWebViewHelper::OnPrintForSystemDialog() {
 962   blink::WebLocalFrame* frame = print_preview_context_.source_frame();
 963   if (!frame) {
 964     NOTREACHED();
 965     return;
 966   }
 967   Print(frame, print_preview_context_.source_node());
 968 }
 969 #endif  // ENABLE_BASIC_PRINTING
 970
 971 void PrintWebViewHelper::GetPageSizeAndContentAreaFromPageLayout(
 972     const PageSizeMargins& page_layout_in_points,
 973     gfx::Size* page_size,
 974     gfx::Rect* content_area) {
 975   *page_size = gfx::Size(
 976       page_layout_in_points.content_width +
 977           page_layout_in_points.margin_right +
 978           page_layout_in_points.margin_left,
 979       page_layout_in_points.content_height +
 980           page_layout_in_points.margin_top +
 981           page_layout_in_points.margin_bottom);
 982   *content_area = gfx::Rect(page_layout_in_points.margin_left,
 983                             page_layout_in_points.margin_top,
 984                             page_layout_in_points.content_width,
 985                             page_layout_in_points.content_height);
 986 }
 987
 988 void PrintWebViewHelper::UpdateFrameMarginsCssInfo(
 989     const base::DictionaryValue& settings) {
 990   int margins_type = 0;
 991   if (!settings.GetInteger(kSettingMarginsType, &margins_type))
 992     margins_type = DEFAULT_MARGINS;
 993   ignore_css_margins_ = (margins_type != DEFAULT_MARGINS);
 994 }
 995
 996 bool PrintWebViewHelper::IsPrintToPdfRequested(
 997     const base::DictionaryValue& job_settings) {
 998   bool print_to_pdf = false;
 999   if (!job_settings.GetBoolean(kSettingPrintToPDF, &print_to_pdf))
1000     NOTREACHED();
1001   return print_to_pdf;
1002 }
1003
1004 void PrintWebViewHelper::OnPrintPreview(const base::DictionaryValue& settings) {
1005   print_preview_context_.OnPrintPreview();
1006
1007   UMA_HISTOGRAM_ENUMERATION("PrintPreview.PreviewEvent",
1008                             PREVIEW_EVENT_REQUESTED, PREVIEW_EVENT_MAX);
1009
1010   if (!print_preview_context_.source_frame()) {
1011     DidFinishPrinting(FAIL_PREVIEW);
1012     return;
1013   }
1014
1015   if (!UpdatePrintSettings(print_preview_context_.source_frame(),
1016                            print_preview_context_.source_node(), settings)) {
1017     if (print_preview_context_.last_error() != PREVIEW_ERROR_BAD_SETTING) {
1018       Send(new PrintHostMsg_PrintPreviewInvalidPrinterSettings(
1019           routing_id(),
1020           print_pages_params_ ?
1021               print_pages_params_->params.document_cookie : 0));
1022       notify_browser_of_print_failure_ = false;  // Already sent.
1023     }
1024     DidFinishPrinting(FAIL_PREVIEW);
1025     return;
1026   }
1027
1028   // Set the options from document if we are previewing a pdf and send a
1029   // message to browser.
1030   if (print_pages_params_->params.is_first_request &&
1031       !print_preview_context_.IsModifiable()) {
1032     PrintHostMsg_SetOptionsFromDocument_Params params;
1033     SetOptionsFromDocument(params);
1034     Send(new PrintHostMsg_SetOptionsFromDocument(routing_id(), params));
1035   }
1036
1037   is_print_ready_metafile_sent_ = false;
1038
1039   // PDF printer device supports alpha blending.
1040   print_pages_params_->params.supports_alpha_blend = true;
1041
1042   bool generate_draft_pages = false;
1043   if (!settings.GetBoolean(kSettingGenerateDraftData,
1044                            &generate_draft_pages)) {
1045     NOTREACHED();
1046   }
1047   print_preview_context_.set_generate_draft_pages(generate_draft_pages);
1048
1049   PrepareFrameForPreviewDocument();
1050 }
1051
1052 void PrintWebViewHelper::PrepareFrameForPreviewDocument() {
1053   reset_prep_frame_view_ = false;
1054
1055   if (!print_pages_params_ || CheckForCancel()) {
1056     DidFinishPrinting(FAIL_PREVIEW);
1057     return;
1058   }
1059
1060   // Don't reset loading frame or WebKit will fail assert. Just retry when
1061   // current selection is loaded.
1062   if (prep_frame_view_ && prep_frame_view_->IsLoadingSelection()) {
1063     reset_prep_frame_view_ = true;
1064     return;
1065   }
1066
1067   const PrintMsg_Print_Params& print_params = print_pages_params_->params;
1068   prep_frame_view_.reset(
1069       new PrepareFrameAndViewForPrint(print_params,
1070                                       print_preview_context_.source_frame(),
1071                                       print_preview_context_.source_node(),
1072                                       ignore_css_margins_));
1073   prep_frame_view_->CopySelectionIfNeeded(
1074       render_view()->GetWebkitPreferences(),
1075       base::Bind(&PrintWebViewHelper::OnFramePreparedForPreviewDocument,
1076                  base::Unretained(this)));
1077 }
1078
1079 void PrintWebViewHelper::OnFramePreparedForPreviewDocument() {
1080   if (reset_prep_frame_view_) {
1081     PrepareFrameForPreviewDocument();
1082     return;
1083   }
1084   DidFinishPrinting(CreatePreviewDocument() ? OK : FAIL_PREVIEW);
1085 }
1086
1087 bool PrintWebViewHelper::CreatePreviewDocument() {
1088   if (!print_pages_params_ || CheckForCancel())
1089     return false;
1090
1091   UMA_HISTOGRAM_ENUMERATION("PrintPreview.PreviewEvent",
1092                             PREVIEW_EVENT_CREATE_DOCUMENT, PREVIEW_EVENT_MAX);
1093
1094   const PrintMsg_Print_Params& print_params = print_pages_params_->params;
1095   const std::vector<int>& pages = print_pages_params_->pages;
1096
1097   if (!print_preview_context_.CreatePreviewDocument(prep_frame_view_.release(),
1098                                                     pages)) {
1099     return false;
1100   }
1101
1102   PageSizeMargins default_page_layout;
1103   ComputePageLayoutInPointsForCss(print_preview_context_.prepared_frame(), 0,
1104                                   print_params, ignore_css_margins_, NULL,
1105                                   &default_page_layout);
1106
1107   bool has_page_size_style = PrintingFrameHasPageSizeStyle(
1108       print_preview_context_.prepared_frame(),
1109       print_preview_context_.total_page_count());
1110   int dpi = GetDPI(&print_params);
1111
1112   gfx::Rect printable_area_in_points(
1113       ConvertUnit(print_params.printable_area.x(), dpi, kPointsPerInch),
1114       ConvertUnit(print_params.printable_area.y(), dpi, kPointsPerInch),
1115       ConvertUnit(print_params.printable_area.width(), dpi, kPointsPerInch),
1116       ConvertUnit(print_params.printable_area.height(), dpi, kPointsPerInch));
1117
1118   // Margins: Send default page layout to browser process.
1119   Send(new PrintHostMsg_DidGetDefaultPageLayout(routing_id(),
1120                                                 default_page_layout,
1121                                                 printable_area_in_points,
1122                                                 has_page_size_style));
1123
1124   PrintHostMsg_DidGetPreviewPageCount_Params params;
1125   params.page_count = print_preview_context_.total_page_count();
1126   params.is_modifiable = print_preview_context_.IsModifiable();
1127   params.document_cookie = print_params.document_cookie;
1128   params.preview_request_id = print_params.preview_request_id;
1129   params.clear_preview_data = print_preview_context_.generate_draft_pages();
1130   Send(new PrintHostMsg_DidGetPreviewPageCount(routing_id(), params));
1131   if (CheckForCancel())
1132     return false;
1133
1134   while (!print_preview_context_.IsFinalPageRendered()) {
1135     int page_number = print_preview_context_.GetNextPageNumber();
1136     DCHECK_GE(page_number, 0);
1137     if (!RenderPreviewPage(page_number, print_params))
1138       return false;
1139
1140     if (CheckForCancel())
1141       return false;
1142
1143     // We must call PrepareFrameAndViewForPrint::FinishPrinting() (by way of
1144     // print_preview_context_.AllPagesRendered()) before calling
1145     // FinalizePrintReadyDocument() when printing a PDF because the plugin
1146     // code does not generate output until we call FinishPrinting().  We do not
1147     // generate draft pages for PDFs, so IsFinalPageRendered() and
1148     // IsLastPageOfPrintReadyMetafile() will be true in the same iteration of
1149     // the loop.
1150     if (print_preview_context_.IsFinalPageRendered())
1151       print_preview_context_.AllPagesRendered();
1152
1153     if (print_preview_context_.IsLastPageOfPrintReadyMetafile()) {
1154       DCHECK(print_preview_context_.IsModifiable() ||
1155              print_preview_context_.IsFinalPageRendered());
1156       if (!FinalizePrintReadyDocument())
1157         return false;
1158     }
1159   }
1160   print_preview_context_.Finished();
1161   return true;
1162 }
1163
1164 bool PrintWebViewHelper::FinalizePrintReadyDocument() {
1165   DCHECK(!is_print_ready_metafile_sent_);
1166   print_preview_context_.FinalizePrintReadyDocument();
1167
1168   // Get the size of the resulting metafile.
1169   PdfMetafileSkia* metafile = print_preview_context_.metafile();
1170   uint32 buf_size = metafile->GetDataSize();
1171   DCHECK_GT(buf_size, 0u);
1172
1173   PrintHostMsg_DidPreviewDocument_Params preview_params;
1174   preview_params.data_size = buf_size;
1175   preview_params.document_cookie = print_pages_params_->params.document_cookie;
1176   preview_params.expected_pages_count =
1177       print_preview_context_.total_page_count();
1178   preview_params.modifiable = print_preview_context_.IsModifiable();
1179   preview_params.preview_request_id =
1180       print_pages_params_->params.preview_request_id;
1181
1182   // Ask the browser to create the shared memory for us.
1183   if (!CopyMetafileDataToSharedMem(metafile,
1184                                    &(preview_params.metafile_data_handle))) {
1185     LOG(ERROR) << "CopyMetafileDataToSharedMem failed";
1186     print_preview_context_.set_error(PREVIEW_ERROR_METAFILE_COPY_FAILED);
1187     return false;
1188   }
1189   is_print_ready_metafile_sent_ = true;
1190
1191   Send(new PrintHostMsg_MetafileReadyForPrinting(routing_id(), preview_params));
1192   return true;
1193 }
1194
1195 void PrintWebViewHelper::OnPrintingDone(bool success) {
1196   notify_browser_of_print_failure_ = false;
1197   if (!success)
1198     LOG(ERROR) << "Failure in OnPrintingDone";
1199   DidFinishPrinting(success ? OK : FAIL_PRINT);
1200 }
1201
1202 void PrintWebViewHelper::SetScriptedPrintBlocked(bool blocked) {
1203   is_scripted_printing_blocked_ = blocked;
1204 }
1205
1206 void PrintWebViewHelper::OnInitiatePrintPreview(bool selection_only) {
1207   blink::WebLocalFrame* frame = NULL;
1208   GetPrintFrame(&frame);
1209   DCHECK(frame);
1210   print_preview_context_.InitWithFrame(frame);
1211   RequestPrintPreview(selection_only ?
1212                       PRINT_PREVIEW_USER_INITIATED_SELECTION :
1213                       PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME);
1214 }
1215
1216 bool PrintWebViewHelper::IsPrintingEnabled() {
1217   bool result = false;
1218   Send(new PrintHostMsg_IsPrintingEnabled(routing_id(), &result));
1219   return result;
1220 }
1221
1222 void PrintWebViewHelper::PrintNode(const blink::WebNode& node) {
1223   if (node.isNull() || !node.document().frame()) {
1224     // This can occur when the context menu refers to an invalid WebNode.
1225     // See http://crbug.com/100890#c17 for a repro case.
1226     return;
1227   }
1228
1229   if (print_node_in_progress_) {
1230     // This can happen as a result of processing sync messages when printing
1231     // from ppapi plugins. It's a rare case, so its OK to just fail here.
1232     // See http://crbug.com/159165.
1233     return;
1234   }
1235
1236   print_node_in_progress_ = true;
1237
1238   // Make a copy of the node, in case RenderView::OnContextMenuClosed resets
1239   // its |context_menu_node_|.
1240   if (!g_is_preview_enabled_) {
1241     blink::WebNode duplicate_node(node);
1242     Print(duplicate_node.document().frame(), duplicate_node);
1243   } else {
1244     print_preview_context_.InitWithNode(node);
1245     RequestPrintPreview(PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE);
1246   }
1247
1248   print_node_in_progress_ = false;
1249 }
1250
1251 void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
1252                                const blink::WebNode& node) {
1253   // If still not finished with earlier print request simply ignore.
1254   if (prep_frame_view_)
1255     return;
1256
1257   FrameReference frame_ref(frame);
1258
1259   int expected_page_count = 0;
1260   if (!CalculateNumberOfPages(frame, node, &expected_page_count)) {
1261     DidFinishPrinting(FAIL_PRINT_INIT);
1262     return;  // Failed to init print page settings.
1263   }
1264
1265   // Some full screen plugins can say they don't want to print.
1266   if (!expected_page_count) {
1267     DidFinishPrinting(FAIL_PRINT);
1268     return;
1269   }
1270
1271   // Ask the browser to show UI to retrieve the final print settings.
1272   if (!GetPrintSettingsFromUser(frame_ref.GetFrame(), node,
1273                                 expected_page_count)) {
1274     DidFinishPrinting(OK);  // Release resources and fail silently.
1275     return;
1276   }
1277
1278   // Render Pages for printing.
1279   if (!RenderPagesForPrint(frame_ref.GetFrame(), node)) {
1280     LOG(ERROR) << "RenderPagesForPrint failed";
1281     DidFinishPrinting(FAIL_PRINT);
1282   }
1283   scripting_throttler_.Reset();
1284 }
1285
1286 void PrintWebViewHelper::DidFinishPrinting(PrintingResult result) {
1287   switch (result) {
1288     case OK:
1289       break;
1290
1291     case FAIL_PRINT_INIT:
1292       DCHECK(!notify_browser_of_print_failure_);
1293       break;
1294
1295     case FAIL_PRINT:
1296       if (notify_browser_of_print_failure_ && print_pages_params_) {
1297         int cookie = print_pages_params_->params.document_cookie;
1298         Send(new PrintHostMsg_PrintingFailed(routing_id(), cookie));
1299       }
1300       break;
1301
1302     case FAIL_PREVIEW:
1303       int cookie = print_pages_params_ ?
1304           print_pages_params_->params.document_cookie : 0;
1305       if (notify_browser_of_print_failure_) {
1306         LOG(ERROR) << "CreatePreviewDocument failed";
1307         Send(new PrintHostMsg_PrintPreviewFailed(routing_id(), cookie));
1308       } else {
1309         Send(new PrintHostMsg_PrintPreviewCancelled(routing_id(), cookie));
1310       }
1311       print_preview_context_.Failed(notify_browser_of_print_failure_);
1312       break;
1313   }
1314   prep_frame_view_.reset();
1315   print_pages_params_.reset();
1316   notify_browser_of_print_failure_ = true;
1317 }
1318
1319 void PrintWebViewHelper::OnFramePreparedForPrintPages() {
1320   PrintPages();
1321   FinishFramePrinting();
1322 }
1323
1324 void PrintWebViewHelper::PrintPages() {
1325   if (!prep_frame_view_)  // Printing is already canceled or failed.
1326     return;
1327   prep_frame_view_->StartPrinting();
1328
1329   int page_count = prep_frame_view_->GetExpectedPageCount();
1330   if (!page_count) {
1331     LOG(ERROR) << "Can't print 0 pages.";
1332     return DidFinishPrinting(FAIL_PRINT);
1333   }
1334
1335   const PrintMsg_PrintPages_Params& params = *print_pages_params_;
1336   const PrintMsg_Print_Params& print_params = params.params;
1337
1338 #if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
1339   // TODO(vitalybuka): should be page_count or valid pages from params.pages.
1340   // See http://crbug.com/161576
1341   Send(new PrintHostMsg_DidGetPrintedPagesCount(routing_id(),
1342                                                 print_params.document_cookie,
1343                                                 page_count));
1344 #endif  // !defined(OS_CHROMEOS)
1345
1346   if (print_params.preview_ui_id < 0) {
1347     // Printing for system dialog.
1348     int printed_count = params.pages.empty() ? page_count : params.pages.size();
1349 #if !defined(OS_CHROMEOS)
1350     UMA_HISTOGRAM_COUNTS("PrintPreview.PageCount.SystemDialog", printed_count);
1351 #else
1352     UMA_HISTOGRAM_COUNTS("PrintPreview.PageCount.PrintToCloudPrintWebDialog",
1353                          printed_count);
1354 #endif  // !defined(OS_CHROMEOS)
1355   }
1356
1357
1358   if (!PrintPagesNative(prep_frame_view_->frame(), page_count)) {
1359     LOG(ERROR) << "Printing failed.";
1360     return DidFinishPrinting(FAIL_PRINT);
1361   }
1362 }
1363
1364 void PrintWebViewHelper::FinishFramePrinting() {
1365   prep_frame_view_.reset();
1366 }
1367
1368 #if defined(OS_MACOSX)
1369 bool PrintWebViewHelper::PrintPagesNative(blink::WebFrame* frame,
1370                                           int page_count) {
1371   const PrintMsg_PrintPages_Params& params = *print_pages_params_;
1372   const PrintMsg_Print_Params& print_params = params.params;
1373
1374   PrintMsg_PrintPage_Params page_params;
1375   page_params.params = print_params;
1376   if (params.pages.empty()) {
1377     for (int i = 0; i < page_count; ++i) {
1378       page_params.page_number = i;
1379       PrintPageInternal(page_params, frame);
1380     }
1381   } else {
1382     for (size_t i = 0; i < params.pages.size(); ++i) {
1383       if (params.pages[i] >= page_count)
1384         break;
1385       page_params.page_number = params.pages[i];
1386       PrintPageInternal(page_params, frame);
1387     }
1388   }
1389   return true;
1390 }
1391
1392 #endif  // OS_MACOSX
1393
1394 // static - Not anonymous so that platform implementations can use it.
1395 void PrintWebViewHelper::ComputePageLayoutInPointsForCss(
1396     blink::WebFrame* frame,
1397     int page_index,
1398     const PrintMsg_Print_Params& page_params,
1399     bool ignore_css_margins,
1400     double* scale_factor,
1401     PageSizeMargins* page_layout_in_points) {
1402   PrintMsg_Print_Params params = CalculatePrintParamsForCss(
1403       frame, page_index, page_params, ignore_css_margins,
1404       page_params.print_scaling_option ==
1405           blink::WebPrintScalingOptionFitToPrintableArea,
1406       scale_factor);
1407   CalculatePageLayoutFromPrintParams(params, page_layout_in_points);
1408 }
1409
1410 bool PrintWebViewHelper::InitPrintSettings(bool fit_to_paper_size) {
1411   PrintMsg_PrintPages_Params settings;
1412   Send(new PrintHostMsg_GetDefaultPrintSettings(routing_id(),
1413                                                 &settings.params));
1414   // Check if the printer returned any settings, if the settings is empty, we
1415   // can safely assume there are no printer drivers configured. So we safely
1416   // terminate.
1417   bool result = true;
1418   if (!PrintMsg_Print_Params_IsValid(settings.params))
1419     result = false;
1420
1421   // Reset to default values.
1422   ignore_css_margins_ = false;
1423   settings.pages.clear();
1424
1425   settings.params.print_scaling_option =
1426       blink::WebPrintScalingOptionSourceSize;
1427   if (fit_to_paper_size) {
1428     settings.params.print_scaling_option =
1429         blink::WebPrintScalingOptionFitToPrintableArea;
1430   }
1431
1432   SetPrintPagesParams(settings);
1433   return result;
1434 }
1435
1436 bool PrintWebViewHelper::CalculateNumberOfPages(blink::WebLocalFrame* frame,
1437                                                 const blink::WebNode& node,
1438                                                 int* number_of_pages) {
1439   DCHECK(frame);
1440   bool fit_to_paper_size = !(PrintingNodeOrPdfFrame(frame, node));
1441   if (!InitPrintSettings(fit_to_paper_size)) {
1442     notify_browser_of_print_failure_ = false;
1443     Send(new PrintHostMsg_ShowInvalidPrinterSettingsError(routing_id()));
1444     return false;
1445   }
1446
1447   const PrintMsg_Print_Params& params = print_pages_params_->params;
1448   PrepareFrameAndViewForPrint prepare(params, frame, node, ignore_css_margins_);
1449   prepare.StartPrinting();
1450
1451   *number_of_pages = prepare.GetExpectedPageCount();
1452   return true;
1453 }
1454
1455 void PrintWebViewHelper::SetOptionsFromDocument(
1456     PrintHostMsg_SetOptionsFromDocument_Params& params) {
1457   blink::WebLocalFrame* source_frame = print_preview_context_.source_frame();
1458   const blink::WebNode& source_node = print_preview_context_.source_node();
1459
1460   params.is_scaling_disabled =
1461       source_frame->isPrintScalingDisabledForPlugin(source_node);
1462 }
1463
1464 bool PrintWebViewHelper::UpdatePrintSettings(
1465     blink::WebLocalFrame* frame,
1466     const blink::WebNode& node,
1467     const base::DictionaryValue& passed_job_settings) {
1468   const base::DictionaryValue* job_settings = &passed_job_settings;
1469   base::DictionaryValue modified_job_settings;
1470   if (job_settings->empty()) {
1471     if (!print_for_preview_)
1472       print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
1473     return false;
1474   }
1475
1476   bool source_is_html = true;
1477   if (print_for_preview_) {
1478     if (!job_settings->GetBoolean(kSettingPreviewModifiable, &source_is_html)) {
1479       NOTREACHED();
1480     }
1481   } else {
1482     source_is_html = !PrintingNodeOrPdfFrame(frame, node);
1483   }
1484
1485   if (print_for_preview_ || !source_is_html) {
1486     modified_job_settings.MergeDictionary(job_settings);
1487     modified_job_settings.SetBoolean(kSettingHeaderFooterEnabled, false);
1488     modified_job_settings.SetInteger(kSettingMarginsType, NO_MARGINS);
1489     job_settings = &modified_job_settings;
1490   }
1491
1492   // Send the cookie so that UpdatePrintSettings can reuse PrinterQuery when
1493   // possible.
1494   int cookie = print_pages_params_ ?
1495       print_pages_params_->params.document_cookie : 0;
1496   PrintMsg_PrintPages_Params settings;
1497   bool canceled = false;
1498   Send(new PrintHostMsg_UpdatePrintSettings(
1499       routing_id(), cookie, *job_settings, &settings, &canceled));
1500   if (canceled) {
1501     notify_browser_of_print_failure_ = false;
1502     return false;
1503   }
1504
1505   if (!job_settings->GetInteger(kPreviewUIID, &settings.params.preview_ui_id)) {
1506     NOTREACHED();
1507     print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
1508     return false;
1509   }
1510
1511   if (!print_for_preview_) {
1512     // Validate expected print preview settings.
1513     if (!job_settings->GetInteger(kPreviewRequestID,
1514                                   &settings.params.preview_request_id) ||
1515         !job_settings->GetBoolean(kIsFirstRequest,
1516                                   &settings.params.is_first_request)) {
1517       NOTREACHED();
1518       print_preview_context_.set_error(PREVIEW_ERROR_BAD_SETTING);
1519       return false;
1520     }
1521
1522     settings.params.print_to_pdf = IsPrintToPdfRequested(*job_settings);
1523     UpdateFrameMarginsCssInfo(*job_settings);
1524     settings.params.print_scaling_option = GetPrintScalingOption(
1525         frame, node, source_is_html, *job_settings, settings.params);
1526   }
1527
1528   SetPrintPagesParams(settings);
1529
1530   if (!PrintMsg_Print_Params_IsValid(settings.params)) {
1531     if (!print_for_preview_)
1532       print_preview_context_.set_error(PREVIEW_ERROR_INVALID_PRINTER_SETTINGS);
1533     else
1534       Send(new PrintHostMsg_ShowInvalidPrinterSettingsError(routing_id()));
1535
1536     return false;
1537   }
1538
1539   return true;
1540 }
1541
1542 bool PrintWebViewHelper::GetPrintSettingsFromUser(blink::WebFrame* frame,
1543                                                   const blink::WebNode& node,
1544                                                   int expected_pages_count) {
1545   PrintHostMsg_ScriptedPrint_Params params;
1546   PrintMsg_PrintPages_Params print_settings;
1547
1548   params.cookie = print_pages_params_->params.document_cookie;
1549   params.has_selection = frame->hasSelection();
1550   params.expected_pages_count = expected_pages_count;
1551   MarginType margin_type = DEFAULT_MARGINS;
1552   if (PrintingNodeOrPdfFrame(frame, node))
1553     margin_type = GetMarginsForPdf(frame, node);
1554   params.margin_type = margin_type;
1555
1556   Send(new PrintHostMsg_DidShowPrintDialog(routing_id()));
1557
1558   // PrintHostMsg_ScriptedPrint will reset print_scaling_option, so we save the
1559   // value before and restore it afterwards.
1560   blink::WebPrintScalingOption scaling_option =
1561       print_pages_params_->params.print_scaling_option;
1562
1563   print_pages_params_.reset();
1564   IPC::SyncMessage* msg =
1565       new PrintHostMsg_ScriptedPrint(routing_id(), params, &print_settings);
1566   msg->EnableMessagePumping();
1567   Send(msg);
1568   print_settings.params.print_scaling_option = scaling_option;
1569   SetPrintPagesParams(print_settings);
1570   return (print_settings.params.dpi && print_settings.params.document_cookie);
1571 }
1572
1573 bool PrintWebViewHelper::RenderPagesForPrint(blink::WebLocalFrame* frame,
1574                                              const blink::WebNode& node) {
1575   if (!frame || prep_frame_view_)
1576     return false;
1577   const PrintMsg_PrintPages_Params& params = *print_pages_params_;
1578   const PrintMsg_Print_Params& print_params = params.params;
1579   prep_frame_view_.reset(new PrepareFrameAndViewForPrint(
1580       print_params, frame, node, ignore_css_margins_));
1581   DCHECK(!print_pages_params_->params.selection_only ||
1582          print_pages_params_->pages.empty());
1583   prep_frame_view_->CopySelectionIfNeeded(
1584       render_view()->GetWebkitPreferences(),
1585       base::Bind(&PrintWebViewHelper::OnFramePreparedForPrintPages,
1586                  base::Unretained(this)));
1587   return true;
1588 }
1589
1590 #if defined(OS_POSIX)
1591 bool PrintWebViewHelper::CopyMetafileDataToSharedMem(
1592     PdfMetafileSkia* metafile,
1593     base::SharedMemoryHandle* shared_mem_handle) {
1594   uint32 buf_size = metafile->GetDataSize();
1595   scoped_ptr<base::SharedMemory> shared_buf(
1596       content::RenderThread::Get()->HostAllocateSharedMemoryBuffer(
1597           buf_size).release());
1598
1599   if (shared_buf) {
1600     if (shared_buf->Map(buf_size)) {
1601       metafile->GetData(shared_buf->memory(), buf_size);
1602       return shared_buf->GiveToProcess(base::GetCurrentProcessHandle(),
1603                                        shared_mem_handle);
1604     }
1605   }
1606   return false;
1607 }
1608 #endif  // defined(OS_POSIX)
1609
1610 void PrintWebViewHelper::ShowScriptedPrintPreview() {
1611   if (is_scripted_preview_delayed_) {
1612     is_scripted_preview_delayed_ = false;
1613     Send(new PrintHostMsg_ShowScriptedPrintPreview(routing_id(),
1614             print_preview_context_.IsModifiable()));
1615   }
1616 }
1617
1618 void PrintWebViewHelper::RequestPrintPreview(PrintPreviewRequestType type) {
1619   const bool is_modifiable = print_preview_context_.IsModifiable();
1620   const bool has_selection = print_preview_context_.HasSelection();
1621   PrintHostMsg_RequestPrintPreview_Params params;
1622   params.is_modifiable = is_modifiable;
1623   params.has_selection = has_selection;
1624   switch (type) {
1625     case PRINT_PREVIEW_SCRIPTED: {
1626       // Shows scripted print preview in two stages.
1627       // 1. PrintHostMsg_SetupScriptedPrintPreview blocks this call and JS by
1628       //    pumping messages here.
1629       // 2. PrintHostMsg_ShowScriptedPrintPreview shows preview once the
1630       //    document has been loaded.
1631       is_scripted_preview_delayed_ = true;
1632       if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
1633         // Wait for DidStopLoading. Plugins may not know the correct
1634         // |is_modifiable| value until they are fully loaded, which occurs when
1635         // DidStopLoading() is called. Defer showing the preview until then.
1636         on_stop_loading_closure_ =
1637             base::Bind(&PrintWebViewHelper::ShowScriptedPrintPreview,
1638                        base::Unretained(this));
1639       } else {
1640         base::MessageLoop::current()->PostTask(
1641             FROM_HERE,
1642             base::Bind(&PrintWebViewHelper::ShowScriptedPrintPreview,
1643                        weak_ptr_factory_.GetWeakPtr()));
1644       }
1645       IPC::SyncMessage* msg =
1646           new PrintHostMsg_SetupScriptedPrintPreview(routing_id());
1647       msg->EnableMessagePumping();
1648       Send(msg);
1649       is_scripted_preview_delayed_ = false;
1650       return;
1651     }
1652     case PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME: {
1653       // Wait for DidStopLoading. Continuing with this function while
1654       // |is_loading_| is true will cause print preview to hang when try to
1655       // print a PDF document.
1656       if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
1657         on_stop_loading_closure_ =
1658             base::Bind(&PrintWebViewHelper::RequestPrintPreview,
1659                        base::Unretained(this),
1660                        type);
1661         return;
1662       }
1663
1664       break;
1665     }
1666     case PRINT_PREVIEW_USER_INITIATED_SELECTION: {
1667       DCHECK(has_selection);
1668       DCHECK(!GetPlugin(print_preview_context_.source_frame()));
1669       params.selection_only = has_selection;
1670       break;
1671     }
1672     case PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE: {
1673       if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
1674         on_stop_loading_closure_ =
1675             base::Bind(&PrintWebViewHelper::RequestPrintPreview,
1676                        base::Unretained(this),
1677                        type);
1678         return;
1679       }
1680
1681       params.webnode_only = true;
1682       break;
1683     }
1684     default: {
1685       NOTREACHED();
1686       return;
1687     }
1688   }
1689   Send(new PrintHostMsg_RequestPrintPreview(routing_id(), params));
1690 }
1691
1692 bool PrintWebViewHelper::CheckForCancel() {
1693   const PrintMsg_Print_Params& print_params = print_pages_params_->params;
1694   bool cancel = false;
1695   Send(new PrintHostMsg_CheckForCancel(routing_id(),
1696                                        print_params.preview_ui_id,
1697                                        print_params.preview_request_id,
1698                                        &cancel));
1699   if (cancel)
1700     notify_browser_of_print_failure_ = false;
1701   return cancel;
1702 }
1703
1704 bool PrintWebViewHelper::PreviewPageRendered(int page_number,
1705                                              PdfMetafileSkia* metafile) {
1706   DCHECK_GE(page_number, FIRST_PAGE_INDEX);
1707
1708   // For non-modifiable files, |metafile| should be NULL, so do not bother
1709   // sending a message. If we don't generate draft metafiles, |metafile| is
1710   // NULL.
1711   if (!print_preview_context_.IsModifiable() ||
1712       !print_preview_context_.generate_draft_pages()) {
1713     DCHECK(!metafile);
1714     return true;
1715   }
1716
1717   if (!metafile) {
1718     NOTREACHED();
1719     print_preview_context_.set_error(
1720         PREVIEW_ERROR_PAGE_RENDERED_WITHOUT_METAFILE);
1721     return false;
1722   }
1723
1724   PrintHostMsg_DidPreviewPage_Params preview_page_params;
1725   // Get the size of the resulting metafile.
1726   uint32 buf_size = metafile->GetDataSize();
1727   DCHECK_GT(buf_size, 0u);
1728   if (!CopyMetafileDataToSharedMem(
1729       metafile, &(preview_page_params.metafile_data_handle))) {
1730     LOG(ERROR) << "CopyMetafileDataToSharedMem failed";
1731     print_preview_context_.set_error(PREVIEW_ERROR_METAFILE_COPY_FAILED);
1732     return false;
1733   }
1734   preview_page_params.data_size = buf_size;
1735   preview_page_params.page_number = page_number;
1736   preview_page_params.preview_request_id =
1737       print_pages_params_->params.preview_request_id;
1738
1739   Send(new PrintHostMsg_DidPreviewPage(routing_id(), preview_page_params));
1740   return true;
1741 }
1742
1743 PrintWebViewHelper::PrintPreviewContext::PrintPreviewContext()
1744     : total_page_count_(0),
1745       current_page_index_(0),
1746       generate_draft_pages_(true),
1747       print_ready_metafile_page_count_(0),
1748       error_(PREVIEW_ERROR_NONE),
1749       state_(UNINITIALIZED) {
1750 }
1751
1752 PrintWebViewHelper::PrintPreviewContext::~PrintPreviewContext() {
1753 }
1754
1755 void PrintWebViewHelper::PrintPreviewContext::InitWithFrame(
1756     blink::WebLocalFrame* web_frame) {
1757   DCHECK(web_frame);
1758   DCHECK(!IsRendering());
1759   state_ = INITIALIZED;
1760   source_frame_.Reset(web_frame);
1761   source_node_.reset();
1762 }
1763
1764 void PrintWebViewHelper::PrintPreviewContext::InitWithNode(
1765     const blink::WebNode& web_node) {
1766   DCHECK(!web_node.isNull());
1767   DCHECK(web_node.document().frame());
1768   DCHECK(!IsRendering());
1769   state_ = INITIALIZED;
1770   source_frame_.Reset(web_node.document().frame());
1771   source_node_ = web_node;
1772 }
1773
1774 void PrintWebViewHelper::PrintPreviewContext::OnPrintPreview() {
1775   DCHECK_EQ(INITIALIZED, state_);
1776   ClearContext();
1777 }
1778
1779 bool PrintWebViewHelper::PrintPreviewContext::CreatePreviewDocument(
1780     PrepareFrameAndViewForPrint* prepared_frame,
1781     const std::vector<int>& pages) {
1782   DCHECK_EQ(INITIALIZED, state_);
1783   state_ = RENDERING;
1784
1785   // Need to make sure old object gets destroyed first.
1786   prep_frame_view_.reset(prepared_frame);
1787   prep_frame_view_->StartPrinting();
1788
1789   total_page_count_ = prep_frame_view_->GetExpectedPageCount();
1790   if (total_page_count_ == 0) {
1791     LOG(ERROR) << "CreatePreviewDocument got 0 page count";
1792     set_error(PREVIEW_ERROR_ZERO_PAGES);
1793     return false;
1794   }
1795
1796   metafile_.reset(new PdfMetafileSkia);
1797   if (!metafile_->Init()) {
1798     set_error(PREVIEW_ERROR_METAFILE_INIT_FAILED);
1799     LOG(ERROR) << "PdfMetafileSkia Init failed";
1800     return false;
1801   }
1802
1803   current_page_index_ = 0;
1804   pages_to_render_ = pages;
1805   // Sort and make unique.
1806   std::sort(pages_to_render_.begin(), pages_to_render_.end());
1807   pages_to_render_.resize(std::unique(pages_to_render_.begin(),
1808                                       pages_to_render_.end()) -
1809                           pages_to_render_.begin());
1810   // Remove invalid pages.
1811   pages_to_render_.resize(std::lower_bound(pages_to_render_.begin(),
1812                                            pages_to_render_.end(),
1813                                            total_page_count_) -
1814                           pages_to_render_.begin());
1815   print_ready_metafile_page_count_ = pages_to_render_.size();
1816   if (pages_to_render_.empty()) {
1817     print_ready_metafile_page_count_ = total_page_count_;
1818     // Render all pages.
1819     for (int i = 0; i < total_page_count_; ++i)
1820       pages_to_render_.push_back(i);
1821   } else if (generate_draft_pages_) {
1822     int pages_index = 0;
1823     for (int i = 0; i < total_page_count_; ++i) {
1824       if (pages_index < print_ready_metafile_page_count_ &&
1825           i == pages_to_render_[pages_index]) {
1826         pages_index++;
1827         continue;
1828       }
1829       pages_to_render_.push_back(i);
1830     }
1831   }
1832
1833   document_render_time_ = base::TimeDelta();
1834   begin_time_ = base::TimeTicks::Now();
1835
1836   return true;
1837 }
1838
1839 void PrintWebViewHelper::PrintPreviewContext::RenderedPreviewPage(
1840     const base::TimeDelta& page_time) {
1841   DCHECK_EQ(RENDERING, state_);
1842   document_render_time_ += page_time;
1843   UMA_HISTOGRAM_TIMES("PrintPreview.RenderPDFPageTime", page_time);
1844 }
1845
1846 void PrintWebViewHelper::PrintPreviewContext::AllPagesRendered() {
1847   DCHECK_EQ(RENDERING, state_);
1848   state_ = DONE;
1849   prep_frame_view_->FinishPrinting();
1850 }
1851
1852 void PrintWebViewHelper::PrintPreviewContext::FinalizePrintReadyDocument() {
1853   DCHECK(IsRendering());
1854
1855   base::TimeTicks begin_time = base::TimeTicks::Now();
1856   metafile_->FinishDocument();
1857
1858   if (print_ready_metafile_page_count_ <= 0) {
1859     NOTREACHED();
1860     return;
1861   }
1862
1863   UMA_HISTOGRAM_MEDIUM_TIMES("PrintPreview.RenderToPDFTime",
1864                              document_render_time_);
1865   base::TimeDelta total_time = (base::TimeTicks::Now() - begin_time) +
1866                                document_render_time_;
1867   UMA_HISTOGRAM_MEDIUM_TIMES("PrintPreview.RenderAndGeneratePDFTime",
1868                              total_time);
1869   UMA_HISTOGRAM_MEDIUM_TIMES("PrintPreview.RenderAndGeneratePDFTimeAvgPerPage",
1870                              total_time / pages_to_render_.size());
1871 }
1872
1873 void PrintWebViewHelper::PrintPreviewContext::Finished() {
1874   DCHECK_EQ(DONE, state_);
1875   state_ = INITIALIZED;
1876   ClearContext();
1877 }
1878
1879 void PrintWebViewHelper::PrintPreviewContext::Failed(bool report_error) {
1880   DCHECK(state_ == INITIALIZED || state_ == RENDERING);
1881   state_ = INITIALIZED;
1882   if (report_error) {
1883     DCHECK_NE(PREVIEW_ERROR_NONE, error_);
1884     UMA_HISTOGRAM_ENUMERATION("PrintPreview.RendererError", error_,
1885                               PREVIEW_ERROR_LAST_ENUM);
1886   }
1887   ClearContext();
1888 }
1889
1890 int PrintWebViewHelper::PrintPreviewContext::GetNextPageNumber() {
1891   DCHECK_EQ(RENDERING, state_);
1892   if (IsFinalPageRendered())
1893     return -1;
1894   return pages_to_render_[current_page_index_++];
1895 }
1896
1897 bool PrintWebViewHelper::PrintPreviewContext::IsRendering() const {
1898   return state_ == RENDERING || state_ == DONE;
1899 }
1900
1901 bool PrintWebViewHelper::PrintPreviewContext::IsModifiable() {
1902   // The only kind of node we can print right now is a PDF node.
1903   return !PrintingNodeOrPdfFrame(source_frame(), source_node_);
1904 }
1905
1906 bool PrintWebViewHelper::PrintPreviewContext::HasSelection() {
1907   return IsModifiable() && source_frame()->hasSelection();
1908 }
1909
1910 bool PrintWebViewHelper::PrintPreviewContext::IsLastPageOfPrintReadyMetafile()
1911     const {
1912   DCHECK(IsRendering());
1913   return current_page_index_ == print_ready_metafile_page_count_;
1914 }
1915
1916 bool  PrintWebViewHelper::PrintPreviewContext::IsFinalPageRendered() const {
1917   DCHECK(IsRendering());
1918   return static_cast<size_t>(current_page_index_) == pages_to_render_.size();
1919 }
1920
1921 void PrintWebViewHelper::PrintPreviewContext::set_generate_draft_pages(
1922     bool generate_draft_pages) {
1923   DCHECK_EQ(INITIALIZED, state_);
1924   generate_draft_pages_ = generate_draft_pages;
1925 }
1926
1927 void PrintWebViewHelper::PrintPreviewContext::set_error(
1928     enum PrintPreviewErrorBuckets error) {
1929   error_ = error;
1930 }
1931
1932 blink::WebLocalFrame* PrintWebViewHelper::PrintPreviewContext::source_frame() {
1933   DCHECK(state_ != UNINITIALIZED);
1934   return source_frame_.GetFrame();
1935 }
1936
1937 const blink::WebNode&
1938     PrintWebViewHelper::PrintPreviewContext::source_node() const {
1939   DCHECK(state_ != UNINITIALIZED);
1940   return source_node_;
1941 }
1942
1943 blink::WebLocalFrame*
1944 PrintWebViewHelper::PrintPreviewContext::prepared_frame() {
1945   DCHECK(state_ != UNINITIALIZED);
1946   return prep_frame_view_->frame();
1947 }
1948
1949 const blink::WebNode&
1950     PrintWebViewHelper::PrintPreviewContext::prepared_node() const {
1951   DCHECK(state_ != UNINITIALIZED);
1952   return prep_frame_view_->node();
1953 }
1954
1955 int PrintWebViewHelper::PrintPreviewContext::total_page_count() const {
1956   DCHECK(state_ != UNINITIALIZED);
1957   return total_page_count_;
1958 }
1959
1960 bool PrintWebViewHelper::PrintPreviewContext::generate_draft_pages() const {
1961   return generate_draft_pages_;
1962 }
1963
1964 PdfMetafileSkia* PrintWebViewHelper::PrintPreviewContext::metafile() {
1965   DCHECK(IsRendering());
1966   return metafile_.get();
1967 }
1968
1969 int PrintWebViewHelper::PrintPreviewContext::last_error() const {
1970   return error_;
1971 }
1972
1973 void PrintWebViewHelper::PrintPreviewContext::ClearContext() {
1974   prep_frame_view_.reset();
1975   metafile_.reset();
1976   pages_to_render_.clear();
1977   error_ = PREVIEW_ERROR_NONE;
1978 }
1979
1980 void PrintWebViewHelper::SetPrintPagesParams(
1981     const PrintMsg_PrintPages_Params& settings) {
1982   print_pages_params_.reset(new PrintMsg_PrintPages_Params(settings));
1983   Send(new PrintHostMsg_DidGetDocumentCookie(routing_id(),
1984                                              settings.params.document_cookie));
1985 }
1986
1987 PrintWebViewHelper::ScriptingThrottler::ScriptingThrottler() : count_(0) {
1988 }
1989
1990 bool PrintWebViewHelper::ScriptingThrottler::IsAllowed(blink::WebFrame* frame) {
1991   const int kMinSecondsToIgnoreJavascriptInitiatedPrint = 2;
1992   const int kMaxSecondsToIgnoreJavascriptInitiatedPrint = 32;
1993   bool too_frequent = false;
1994
1995   // Check if there is script repeatedly trying to print and ignore it if too
1996   // frequent.  The first 3 times, we use a constant wait time, but if this
1997   // gets excessive, we switch to exponential wait time. So for a page that
1998   // calls print() in a loop the user will need to cancel the print dialog
1999   // after: [2, 2, 2, 4, 8, 16, 32, 32, ...] seconds.
2000   // This gives the user time to navigate from the page.
2001   if (count_ > 0) {
2002     base::TimeDelta diff = base::Time::Now() - last_print_;
2003     int min_wait_seconds = kMinSecondsToIgnoreJavascriptInitiatedPrint;
2004     if (count_ > 3) {
2005       min_wait_seconds =
2006           std::min(kMinSecondsToIgnoreJavascriptInitiatedPrint << (count_ - 3),
2007                    kMaxSecondsToIgnoreJavascriptInitiatedPrint);
2008     }
2009     if (diff.InSeconds() < min_wait_seconds) {
2010       too_frequent = true;
2011     }
2012   }
2013
2014   if (!too_frequent) {
2015     ++count_;
2016     last_print_ = base::Time::Now();
2017     return true;
2018   }
2019
2020   blink::WebString message(
2021       blink::WebString::fromUTF8("Ignoring too frequent calls to print()."));
2022   frame->addMessageToConsole(blink::WebConsoleMessage(
2023       blink::WebConsoleMessage::LevelWarning, message));
2024   return false;
2025 }
2026
2027 void PrintWebViewHelper::ScriptingThrottler::Reset() {
2028   // Reset counter on successful print.
2029   count_ = 0;
2030 }
2031
2032 }  // namespace printing