Query the preferred readback config in CopyFromBackingStore

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"
 #include "ipc/ipc_channel.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "third_party/WebKit/public/web/WebTextDirection.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/size.h"
 #include "ui/surface/transport_dib.h"
 
 #if defined(TOOLKIT_GTK)
 #include "ui/base/x/x11_util.h"
 #elif defined(OS_MACOSX)
 #include "skia/ext/platform_device.h"
 #endif
 
 class SkBitmap;
@@ skipping 165 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) = 0;
+      const base::Callback<void(bool, const SkBitmap&)>& callback,
+      const SkBitmap::Config& bitmap_config) = 0;
 #if defined(TOOLKIT_GTK)
   // Paint the backing store into the target's |dest_rect|.
   virtual bool CopyFromBackingStoreToGtkWindow(const gfx::Rect& dest_rect,
                                                GdkWindow* target) = 0;
 #elif defined(OS_MACOSX)
   virtual gfx::Size GetBackingStoreSize() = 0;
   virtual bool CopyFromBackingStoreToCGContext(const CGRect& dest_rect,
                                                CGContextRef target) = 0;
 #endif
 
@@ skipping 76 matching lines @@
   // Grabs snapshot from renderer side and returns the bitmap to a callback.
   // If |src_rect| is empty, the whole contents is copied. This is an expensive
   // operation due to the IPC, but it can be used as a fallback method when
   // CopyFromBackingStore fails due to the backing store not being available or,
   // in composited mode, when the accelerated surface is not available to the
   // browser side.
   virtual void GetSnapshotFromRenderer(
       const gfx::Rect& src_subrect,
       const base::Callback<void(bool, const SkBitmap&)>& callback) = 0;
 
+  virtual SkBitmap::Config PreferredReadbackFormat() = 0;
+
  protected:
   friend class RenderWidgetHostImpl;
 
   // Retrieves the implementation class.  Intended only for code
   // 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_