Introduce PlatformBitmap, which is a minimal helper class that wraps an SkBitmap

chrome/browser/thumbnails/thumbnail_tab_helper.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_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
 #define CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 class GURL;
 class Profile;
 class SkBitmap;
 
 namespace content {
 class RenderViewHost;
 class RenderWidgetHost;
 }
 
 namespace history {
 class TopSites;
 }
 
 namespace skia {
-class PlatformCanvas;
+class PlatformBitmap;
 }
 
 class ThumbnailTabHelper
     : public content::NotificationObserver,
       public content::WebContentsObserver,
       public content::WebContentsUserData<ThumbnailTabHelper> {
  public:
   // The result of clipping. This can be used to determine if the
   // generated thumbnail is good or not.
   enum ClipResult {
@@ skipping 73 matching lines @@
   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,
+      skia::PlatformBitmap* temp_bitmap,
       bool result);
 
   // Called when a render view host was created for a WebContents.
   void RenderViewHostCreated(content::RenderViewHost* renderer);
 
   // Indicates that the given widget has changed is visibility.
   void WidgetHidden(content::RenderWidgetHost* widget);
 
   // Called when the given render view host was deleted.
   void RenderViewHostDeleted(content::RenderViewHost* renderer);
 
   bool enabled_;
 
   content::NotificationRegistrar registrar_;
 
   bool load_interrupted_;
 
   base::WeakPtrFactory<ThumbnailTabHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailTabHelper);
 };
 
 #endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_