Support error handling for Surface readbacks

content/public/browser/render_widget_host.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 CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_H_
 
 #include "base/callback.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/native_web_keyboard_event.h"
@@ skipping 162 matching lines @@
   // resized. If |accelerated_dst_size| is empty, the size copied from the
   // source contents is used. |callback| is invoked with true on success, false
   // otherwise, along with a SkBitmap containing the copied pixel data.
   //
   // NOTE: |callback| is called synchronously if the backing store is available.
   // When accelerated compositing is active, |callback| may be called
   // asynchronously.
   virtual void CopyFromBackingStore(
       const gfx::Rect& src_rect,
       const gfx::Size& accelerated_dst_size,
-      const base::Callback<void(bool, const SkBitmap&)>& callback,
+      const base::Callback<void(bool, const SkBitmap&, const int&)>& callback,
       const SkColorType color_type) = 0;
   // Ensures that the view does not drop the backing store even when hidden.
   virtual bool CanCopyFromBackingStore() = 0;
 #if defined(OS_ANDROID)
   virtual void LockBackingStore() = 0;
   virtual void UnlockBackingStore() = 0;
 #endif
 
   // Forwards the given message to the renderer. These are called by
   // the view when it has received a message.
@@ skipping 64 matching lines @@
   // within content/.  This method is necessary because
   // RenderWidgetHost is the root of a diamond inheritance pattern, so
   // subclasses inherit it virtually, which removes our ability to
   // static_cast to the subclass.
   virtual RenderWidgetHostImpl* AsRenderWidgetHostImpl() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_H_