Clip the bitmap for creating the thumbnail on GPU when accelerated compositing is active.

chrome/browser/tab_contents/thumbnail_generator.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_TAB_CONTENTS_THUMBNAIL_GENERATOR_H_
 #define CHROME_BROWSER_TAB_CONTENTS_THUMBNAIL_GENERATOR_H_
 
 #include <map>
 #include <utility>
 #include <vector>
@@ skipping 27 matching lines @@
 class PlatformCanvas;
 }
 
 class ThumbnailGenerator : public content::NotificationObserver,
                            public content::WebContentsObserver {
  public:
   typedef base::Callback<void(const SkBitmap&)> ThumbnailReadyCallback;
   // The result of clipping. This can be used to determine if the
   // generated thumbnail is good or not.
   enum ClipResult {
+    // Clipping is not done yet.
+    kUnprocessed,
     // The source image is smaller.
     kSourceIsSmaller,
     // Wider than tall by twice or more, clip horizontally.
     kTooWiderThanTall,
     // Wider than tall, clip horizontally.
     kWiderThanTall,
     // Taller than wide, clip vertically.
     kTallerThanWide,
     // The source and destination aspect ratios are identical.
     kNotClipped,
@@ skipping 48 matching lines @@
                                    int desired_width,
                                    int desired_height,
                                    ClipResult* clip_result);
 
   // Update the thumbnail of the given tab contents if necessary.
   void UpdateThumbnailIfNecessary(content::WebContents* webb_contents);
 
   // Update the thumbnail of the given tab.
   void UpdateThumbnail(content::WebContents* web_contents,
                        const SkBitmap& bitmap,
-                       const ThumbnailGenerator::ClipResult& clip_result);
+                       const ClipResult& clip_result);
 
   // Returns true if we should update the thumbnail of the given URL.
   static bool ShouldUpdateThumbnail(Profile* profile,
                                     history::TopSites* top_sites,
                                     const GURL& url);
 
   // content::WebContentsObserver overrides.
   virtual void DidStartLoading(
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void StopNavigation() OVERRIDE;
 
  private:
   virtual void WidgetDidReceivePaintAtSizeAck(
       content::RenderWidgetHost* widget,
       int tag,
       const gfx::Size& size);
 
   // Asynchronously updates the thumbnail of the given tab. The caller must
   // ensure that |web_contents| outlives ThumbnailGenerator so that the
   // asynchronous callback can accesses |web_contents|. This must be called on
   // the UI thread.
   void AsyncUpdateThumbnail(content::WebContents* web_contents);
 
   // Called when the bitmap for generating a thumbnail is ready after the
   // AsyncUpdateThumbnail invocation. This runs on the UI thread.
   void UpdateThumbnailWithBitmap(
       content::WebContents* web_contents,
+      ClipResult clip_result,
       const SkBitmap& bitmap);
 
   // Called when the canvas for generating a thumbnail is ready after the
   // AsyncUpdateThumbnail invocation. This runs on the UI thread.
   void UpdateThumbnailWithCanvas(
       content::WebContents* web_contents,
+      ClipResult clip_result,
       skia::PlatformCanvas* temp_canvas,
       bool result);
 
   // content::NotificationObserver interface.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // Indicates that the given widget has changed is visibility.
   void WidgetHidden(content::RenderWidgetHost* widget);
@@ skipping 12 matching lines @@
   ThumbnailCallbackMap callback_map_;
 
   bool load_interrupted_;
 
   base::WeakPtrFactory<ThumbnailGenerator> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailGenerator);
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_THUMBNAIL_GENERATOR_H_