Query the preferred readback config in CopyFromBackingStore

content/browser/renderer_host/render_widget_host_view_aura.cc

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 3565 matching lines @@
 void RenderWidgetHostViewAura::LockResources() {
   DCHECK(frame_provider_);
   delegated_frame_evictor_->LockFrame();
 }
 
 void RenderWidgetHostViewAura::UnlockResources() {
   DCHECK(frame_provider_);
   delegated_frame_evictor_->UnlockFrame();
 }
 
+SkBitmap::Config RenderWidgetHostViewAura::PreferredReadbackFormat() {
+  return SkBitmap::kARGB_8888_Config;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostView, public:
 
 // static
 RenderWidgetHostView* RenderWidgetHostView::CreateViewForWidget(
     RenderWidgetHost* widget) {
   return new RenderWidgetHostViewAura(widget);
 }
 
 // static
 void RenderWidgetHostViewPort::GetDefaultScreenInfo(WebScreenInfo* results) {
   GetScreenInfoForWindow(results, NULL);
 }
 
 }  // namespace content