src/chrome/browser/thumbnails/thumbnail_tab_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/browser/thumbnails/thumbnail_tab_helper.h"
   6
   7 #include "chrome/browser/browser_process.h"
   8 #include "chrome/browser/profiles/profile.h"
   9 #include "chrome/browser/thumbnails/thumbnail_service.h"
  10 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
  11 #include "chrome/browser/thumbnails/thumbnailing_algorithm.h"
  12 #include "chrome/browser/thumbnails/thumbnailing_context.h"
  13 #include "content/public/browser/notification_details.h"
  14 #include "content/public/browser/notification_source.h"
  15 #include "content/public/browser/notification_types.h"
  16 #include "content/public/browser/render_view_host.h"
  17 #include "content/public/browser/render_widget_host_view.h"
  18 #include "ui/gfx/color_utils.h"
  19 #include "ui/gfx/size_conversions.h"
  20 #include "ui/gfx/screen.h"
  21 #include "ui/gfx/scrollbar_size.h"
  22 #include "ui/gfx/skbitmap_operations.h"
  23
  24 #if defined(OS_WIN)
  25 #include "base/win/windows_version.h"
  26 #endif
  27
  28 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ThumbnailTabHelper);
  29
  30 class SkBitmap;
  31
  32 // Overview
  33 // --------
  34 // This class provides a service for updating thumbnails to be used in
  35 // "Most visited" section of the new tab page. The service can be started
  36 // by StartThumbnailing(). The current algorithm of the service is as
  37 // simple as follows:
  38 //
  39 //    When a renderer is about to be hidden (this usually occurs when the
  40 //    current tab is closed or another tab is clicked), update the
  41 //    thumbnail for the tab rendered by the renderer, if needed. The
  42 //    heuristics to judge whether or not to update the thumbnail is
  43 //    implemented in ShouldUpdateThumbnail().
  44
  45 using content::RenderViewHost;
  46 using content::RenderWidgetHost;
  47 using content::WebContents;
  48
  49 using thumbnails::ClipResult;
  50 using thumbnails::ThumbnailingContext;
  51 using thumbnails::ThumbnailingAlgorithm;
  52
  53 namespace {
  54
  55 // Feed the constructed thumbnail to the thumbnail service.
  56 void UpdateThumbnail(const ThumbnailingContext& context,
  57                      const SkBitmap& thumbnail) {
  58   gfx::Image image = gfx::Image::CreateFrom1xBitmap(thumbnail);
  59   context.service->SetPageThumbnail(context, image);
  60   VLOG(1) << "Thumbnail taken for " << context.url << ": "
  61           << context.score.ToString();
  62 }
  63
  64 void ProcessCapturedBitmap(scoped_refptr<ThumbnailingContext> context,
  65                            scoped_refptr<ThumbnailingAlgorithm> algorithm,
  66                            bool succeeded,
  67                            const SkBitmap& bitmap) {
  68   if (!succeeded)
  69     return;
  70
  71   // On success, we must be on the UI thread (on failure because of shutdown we
  72   // are not on the UI thread).
  73   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  74
  75   algorithm->ProcessBitmap(context, base::Bind(&UpdateThumbnail), bitmap);
  76 }
  77
  78 void GotSnapshotFromRenderer(base::Callback<void(const SkBitmap&)> callback,
  79                              bool success,
  80                              const SkBitmap& bitmap) {
  81   if (success)
  82     callback.Run(bitmap);
  83 }
  84
  85 void AsyncProcessThumbnail(content::WebContents* web_contents,
  86                            scoped_refptr<ThumbnailingContext> context,
  87                            scoped_refptr<ThumbnailingAlgorithm> algorithm) {
  88   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  89   RenderWidgetHost* render_widget_host = web_contents->GetRenderViewHost();
  90   content::RenderWidgetHostView* view = render_widget_host->GetView();
  91   if (!view)
  92     return;
  93   if (!view->IsSurfaceAvailableForCopy()) {
  94     // On Windows XP and possibly due to driver issues, neither the backing
  95     // store nor the compositing surface is available in the browser when
  96     // accelerated compositing is active, so ask the renderer to send a snapshot
  97     // for creating the thumbnail.
  98     render_widget_host->GetSnapshotFromRenderer(
  99       gfx::Rect(),
 100       base::Bind(GotSnapshotFromRenderer, base::Bind(
 101           &ThumbnailingAlgorithm::ProcessBitmap,
 102           algorithm, context, base::Bind(&UpdateThumbnail))));
 103     return;
 104   }
 105
 106   gfx::Rect copy_rect = gfx::Rect(view->GetViewBounds().size());
 107   // Clip the pixels that will commonly hold a scrollbar, which looks bad in
 108   // thumbnails.
 109   int scrollbar_size = gfx::scrollbar_size();
 110   gfx::Size copy_size;
 111   copy_rect.Inset(0, 0, scrollbar_size, scrollbar_size);
 112
 113   if (copy_rect.IsEmpty())
 114     return;
 115
 116   context->clip_result = algorithm->GetCanvasCopyInfo(
 117       copy_rect.size(),
 118       ui::GetScaleFactorForNativeView(view->GetNativeView()),
 119       &copy_rect,
 120       &context->requested_copy_size);
 121
 122   render_widget_host->CopyFromBackingStore(
 123       copy_rect,
 124       context->requested_copy_size,
 125       base::Bind(&ProcessCapturedBitmap, context, algorithm));
 126 }
 127
 128 }  // namespace
 129
 130 ThumbnailTabHelper::ThumbnailTabHelper(content::WebContents* contents)
 131     : content::WebContentsObserver(contents),
 132       enabled_(true),
 133       load_interrupted_(false) {
 134   // Even though we deal in RenderWidgetHosts, we only care about its
 135   // subclass, RenderViewHost when it is in a tab. We don't make thumbnails
 136   // for RenderViewHosts that aren't in tabs, or RenderWidgetHosts that
 137   // aren't views like select popups.
 138   registrar_.Add(this,
 139                  content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED,
 140                  content::Source<WebContents>(contents));
 141 }
 142
 143 ThumbnailTabHelper::~ThumbnailTabHelper() {
 144 }
 145
 146 void ThumbnailTabHelper::Observe(int type,
 147                                  const content::NotificationSource& source,
 148                                  const content::NotificationDetails& details) {
 149   switch (type) {
 150     case content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED:
 151       RenderViewHostCreated(content::Details<RenderViewHost>(details).ptr());
 152       break;
 153
 154     case content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED:
 155       if (!*content::Details<bool>(details).ptr())
 156         WidgetHidden(content::Source<RenderWidgetHost>(source).ptr());
 157       break;
 158
 159     default:
 160       NOTREACHED() << "Unexpected notification type: " << type;
 161   }
 162 }
 163
 164 void ThumbnailTabHelper::RenderViewDeleted(
 165     content::RenderViewHost* render_view_host) {
 166   bool registered = registrar_.IsRegistered(
 167       this,
 168       content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 169       content::Source<RenderWidgetHost>(render_view_host));
 170   if (registered) {
 171     registrar_.Remove(
 172         this,
 173         content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 174         content::Source<RenderWidgetHost>(render_view_host));
 175   }
 176 }
 177
 178 void ThumbnailTabHelper::DidStartLoading(
 179     content::RenderViewHost* render_view_host) {
 180   load_interrupted_ = false;
 181 }
 182
 183 void ThumbnailTabHelper::NavigationStopped() {
 184   // This function gets called when the page loading is interrupted by the
 185   // stop button.
 186   load_interrupted_ = true;
 187 }
 188
 189 void ThumbnailTabHelper::UpdateThumbnailIfNecessary(
 190     WebContents* web_contents) {
 191   // Destroying a WebContents may trigger it to be hidden, prompting a snapshot
 192   // which would be unwise to attempt <http://crbug.com/130097>. If the
 193   // WebContents is in the middle of destruction, do not risk it.
 194   if (!web_contents || web_contents->IsBeingDestroyed())
 195     return;
 196   // Skip if a pending entry exists. WidgetHidden can be called while navigating
 197   // pages and this is not a time when thumbnails should be generated.
 198   if (web_contents->GetController().GetPendingEntry())
 199     return;
 200   const GURL& url = web_contents->GetURL();
 201   Profile* profile =
 202       Profile::FromBrowserContext(web_contents->GetBrowserContext());
 203
 204   scoped_refptr<thumbnails::ThumbnailService> thumbnail_service =
 205       ThumbnailServiceFactory::GetForProfile(profile);
 206
 207   // Skip if we don't need to update the thumbnail.
 208   if (thumbnail_service.get() == NULL ||
 209       !thumbnail_service->ShouldAcquirePageThumbnail(url)) {
 210     return;
 211   }
 212
 213   scoped_refptr<thumbnails::ThumbnailingAlgorithm> algorithm(
 214       thumbnail_service->GetThumbnailingAlgorithm());
 215
 216   scoped_refptr<ThumbnailingContext> context(new ThumbnailingContext(
 217       web_contents, thumbnail_service.get(), load_interrupted_));
 218   AsyncProcessThumbnail(web_contents, context, algorithm);
 219 }
 220
 221 void ThumbnailTabHelper::RenderViewHostCreated(
 222     content::RenderViewHost* renderer) {
 223   // NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED is really a new
 224   // RenderView, not RenderViewHost, and there is no good way to get
 225   // notifications of RenderViewHosts. So just be tolerant of re-registrations.
 226   bool registered = registrar_.IsRegistered(
 227       this,
 228       content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 229       content::Source<RenderWidgetHost>(renderer));
 230   if (!registered) {
 231     registrar_.Add(
 232         this,
 233         content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 234         content::Source<RenderWidgetHost>(renderer));
 235   }
 236 }
 237
 238 void ThumbnailTabHelper::WidgetHidden(RenderWidgetHost* widget) {
 239   if (!enabled_)
 240     return;
 241   UpdateThumbnailIfNecessary(web_contents());
 242 }