Allow CopyFromBackingStore to fallback to copying from the renderer side if the accelerated surface…

chrome/browser/ui/snapshot_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_UI_SNAPSHOT_TAB_HELPER_H_
-#define CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_
-
-#include "content/public/browser/web_contents_observer.h"
-#include "content/public/browser/web_contents_user_data.h"
-
-class SkBitmap;
-
-// Per-tab class to handle snapshot functionality.
-class SnapshotTabHelper
-    : public content::WebContentsObserver,
-      public content::WebContentsUserData<SnapshotTabHelper> {
- public:
-  virtual ~SnapshotTabHelper();
-
-  // Captures a snapshot of the page.
-  void CaptureSnapshot();
-
- private:
-  explicit SnapshotTabHelper(content::WebContents* web_contents);
-  friend class content::WebContentsUserData<SnapshotTabHelper>;
-
-  // content::WebContentsObserver overrides:
-  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
-
-  // Internal helpers ----------------------------------------------------------
-
-  // Message handler.
-  void OnSnapshot(const SkBitmap& bitmap);
-
-  DISALLOW_COPY_AND_ASSIGN(SnapshotTabHelper);
-};
-
-#endif  // CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_