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/render_widget_snapshot_taker.h"
  10 #include "chrome/browser/thumbnails/thumbnail_service.h"
  11 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
  12 #include "chrome/browser/thumbnails/thumbnailing_algorithm.h"
  13 #include "chrome/browser/thumbnails/thumbnailing_context.h"
  14 #include "content/public/browser/notification_details.h"
  15 #include "content/public/browser/notification_source.h"
  16 #include "content/public/browser/notification_types.h"
  17 #include "content/public/browser/render_view_host.h"
  18 #include "content/public/browser/render_widget_host_view.h"
  19 #include "ui/gfx/color_utils.h"
  20 #include "ui/gfx/size_conversions.h"
  21 #include "ui/gfx/screen.h"
  22 #include "ui/gfx/scrollbar_size.h"
  23 #include "ui/gfx/skbitmap_operations.h"
  24
  25 #if defined(OS_WIN)
  26 #include "base/win/windows_version.h"
  27 #endif
  28
  29 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ThumbnailTabHelper);
  30
  31 class SkBitmap;
  32
  33 // Overview
  34 // --------
  35 // This class provides a service for updating thumbnails to be used in
  36 // "Most visited" section of the new tab page. The service can be started
  37 // by StartThumbnailing(). The current algorithm of the service is as
  38 // simple as follows:
  39 //
  40 //    When a renderer is about to be hidden (this usually occurs when the
  41 //    current tab is closed or another tab is clicked), update the
  42 //    thumbnail for the tab rendered by the renderer, if needed. The
  43 //    heuristics to judge whether or not to update the thumbnail is
  44 //    implemented in ShouldUpdateThumbnail().
  45
  46 using content::RenderViewHost;
  47 using content::RenderWidgetHost;
  48 using content::WebContents;
  49
  50 using thumbnails::ClipResult;
  51 using thumbnails::ThumbnailingContext;
  52 using thumbnails::ThumbnailingAlgorithm;
  53
  54 namespace {
  55
  56 // Feed the constructed thumbnail to the thumbnail service.
  57 void UpdateThumbnail(const ThumbnailingContext& context,
  58                      const SkBitmap& thumbnail) {
  59   gfx::Image image = gfx::Image::CreateFrom1xBitmap(thumbnail);
  60   context.service->SetPageThumbnail(context, image);
  61   VLOG(1) << "Thumbnail taken for " << context.url << ": "
  62           << context.score.ToString();
  63 }
  64
  65 void ProcessCapturedBitmap(scoped_refptr<ThumbnailingContext> context,
  66                            scoped_refptr<ThumbnailingAlgorithm> algorithm,
  67                            bool succeeded,
  68                            const SkBitmap& bitmap) {
  69   if (!succeeded)
  70     return;
  71
  72   // On success, we must be on the UI thread (on failure because of shutdown we
  73   // are not on the UI thread).
  74   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  75
  76   algorithm->ProcessBitmap(context, base::Bind(&UpdateThumbnail), bitmap);
  77 }
  78
  79 void GotSnapshotFromRenderer(base::Callback<void(const SkBitmap&)> callback,
  80                              bool success,
  81                              const SkBitmap& bitmap) {
  82   if (success)
  83     callback.Run(bitmap);
  84 }
  85
  86 void AsyncProcessThumbnail(content::WebContents* web_contents,
  87                            scoped_refptr<ThumbnailingContext> context,
  88                            scoped_refptr<ThumbnailingAlgorithm> algorithm) {
  89   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
  90   RenderWidgetHost* render_widget_host = web_contents->GetRenderViewHost();
  91   content::RenderWidgetHostView* view = render_widget_host->GetView();
  92   if (!view)
  93     return;
  94   if (!view->IsSurfaceAvailableForCopy()) {
  95     // On Windows XP and possibly due to driver issues, neither the backing
  96     // store nor the compositing surface is available in the browser when
  97     // accelerated compositing is active, so ask the renderer to send a snapshot
  98     // for creating the thumbnail.
  99     render_widget_host->GetSnapshotFromRenderer(
 100       gfx::Rect(),
 101       base::Bind(GotSnapshotFromRenderer, base::Bind(
 102           &ThumbnailingAlgorithm::ProcessBitmap,
 103           algorithm, context, base::Bind(&UpdateThumbnail))));
 104     return;
 105   }
 106
 107   gfx::Rect copy_rect = gfx::Rect(view->GetViewBounds().size());
 108   // Clip the pixels that will commonly hold a scrollbar, which looks bad in
 109   // thumbnails.
 110   int scrollbar_size = gfx::scrollbar_size();
 111   gfx::Size copy_size;
 112   copy_rect.Inset(0, 0, scrollbar_size, scrollbar_size);
 113
 114   if (copy_rect.IsEmpty())
 115     return;
 116
 117   context->clip_result = algorithm->GetCanvasCopyInfo(
 118       copy_rect.size(),
 119       ui::GetScaleFactorForNativeView(view->GetNativeView()),
 120       &copy_rect,
 121       &context->requested_copy_size);
 122
 123   render_widget_host->CopyFromBackingStore(
 124       copy_rect,
 125       context->requested_copy_size,
 126       base::Bind(&ProcessCapturedBitmap, context, algorithm));
 127 }
 128
 129 }  // namespace
 130
 131 ThumbnailTabHelper::ThumbnailTabHelper(content::WebContents* contents)
 132     : content::WebContentsObserver(contents),
 133       enabled_(true),
 134       load_interrupted_(false) {
 135   // Even though we deal in RenderWidgetHosts, we only care about its
 136   // subclass, RenderViewHost when it is in a tab. We don't make thumbnails
 137   // for RenderViewHosts that aren't in tabs, or RenderWidgetHosts that
 138   // aren't views like select popups.
 139   registrar_.Add(this,
 140                  content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED,
 141                  content::Source<WebContents>(contents));
 142 }
 143
 144 ThumbnailTabHelper::~ThumbnailTabHelper() {
 145 }
 146
 147 void ThumbnailTabHelper::Observe(int type,
 148                                  const content::NotificationSource& source,
 149                                  const content::NotificationDetails& details) {
 150   switch (type) {
 151     case content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED:
 152       RenderViewHostCreated(content::Details<RenderViewHost>(details).ptr());
 153       break;
 154
 155     case content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED:
 156       if (!*content::Details<bool>(details).ptr())
 157         WidgetHidden(content::Source<RenderWidgetHost>(source).ptr());
 158       break;
 159
 160     default:
 161       NOTREACHED() << "Unexpected notification type: " << type;
 162   }
 163 }
 164
 165 void ThumbnailTabHelper::RenderViewDeleted(
 166     content::RenderViewHost* render_view_host) {
 167   g_browser_process->GetRenderWidgetSnapshotTaker()->CancelSnapshot(
 168       render_view_host);
 169
 170   bool registered = registrar_.IsRegistered(
 171       this,
 172       content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 173       content::Source<RenderWidgetHost>(render_view_host));
 174   if (registered) {
 175     registrar_.Remove(
 176         this,
 177         content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 178         content::Source<RenderWidgetHost>(render_view_host));
 179   }
 180 }
 181
 182 void ThumbnailTabHelper::DidStartLoading(
 183     content::RenderViewHost* render_view_host) {
 184   load_interrupted_ = false;
 185 }
 186
 187 void ThumbnailTabHelper::NavigationStopped() {
 188   // This function gets called when the page loading is interrupted by the
 189   // stop button.
 190   load_interrupted_ = true;
 191 }
 192
 193 void ThumbnailTabHelper::UpdateThumbnailIfNecessary(
 194     WebContents* web_contents) {
 195   // Destroying a WebContents may trigger it to be hidden, prompting a snapshot
 196   // which would be unwise to attempt <http://crbug.com/130097>. If the
 197   // WebContents is in the middle of destruction, do not risk it.
 198   if (!web_contents || web_contents->IsBeingDestroyed())
 199     return;
 200   // Skip if a pending entry exists. WidgetHidden can be called while navigating
 201   // pages and this is not a time when thumbnails should be generated.
 202   if (web_contents->GetController().GetPendingEntry())
 203     return;
 204   const GURL& url = web_contents->GetURL();
 205   Profile* profile =
 206       Profile::FromBrowserContext(web_contents->GetBrowserContext());
 207
 208   scoped_refptr<thumbnails::ThumbnailService> thumbnail_service =
 209       ThumbnailServiceFactory::GetForProfile(profile);
 210
 211   // Skip if we don't need to update the thumbnail.
 212   if (thumbnail_service.get() == NULL ||
 213       !thumbnail_service->ShouldAcquirePageThumbnail(url)) {
 214     return;
 215   }
 216
 217   scoped_refptr<thumbnails::ThumbnailingAlgorithm> algorithm(
 218       thumbnail_service->GetThumbnailingAlgorithm());
 219
 220   scoped_refptr<ThumbnailingContext> context(new ThumbnailingContext(
 221       web_contents, thumbnail_service.get(), load_interrupted_));
 222   AsyncProcessThumbnail(web_contents, context, algorithm);
 223 }
 224
 225 void ThumbnailTabHelper::RenderViewHostCreated(
 226     content::RenderViewHost* renderer) {
 227   // NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED is really a new
 228   // RenderView, not RenderViewHost, and there is no good way to get
 229   // notifications of RenderViewHosts. So just be tolerant of re-registrations.
 230   bool registered = registrar_.IsRegistered(
 231       this,
 232       content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 233       content::Source<RenderWidgetHost>(renderer));
 234   if (!registered) {
 235     registrar_.Add(
 236         this,
 237         content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 238         content::Source<RenderWidgetHost>(renderer));
 239   }
 240 }
 241
 242 void ThumbnailTabHelper::WidgetHidden(RenderWidgetHost* widget) {
 243   if (!enabled_)
 244     return;
 245   UpdateThumbnailIfNecessary(web_contents());
 246 }