Support browser side thumbnailing for GPU composited pages on Windows.

ui/gfx/surface/accelerated_surface_win.h

Index: ui/gfx/surface/accelerated_surface_win.h
diff --git a/ui/gfx/surface/accelerated_surface_win.h b/ui/gfx/surface/accelerated_surface_win.h
index 5ed30782a099a425ab218d220a521cf1f5107929..5634b9c2e1bc3225848792998b02819f120a39f5 100644
--- a/ui/gfx/surface/accelerated_surface_win.h
+++ b/ui/gfx/surface/accelerated_surface_win.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <d3d9.h>
+#include <vector>
 
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
@@ -28,6 +29,7 @@ class AcceleratedPresenter : public base::RefCounted<AcceleratedPresenter> {
                                   int64 surface_id,
                                   const base::Closure& completion_task);
   bool Present(gfx::NativeWindow window);
+  bool CopyTo(const gfx::Size& size, std::vector<unsigned char>* buf);
   void Suspend();
   void WaitForPendingTasks();
 
@@ -79,6 +81,10 @@ class SURFACE_EXPORT AcceleratedSurface {
   // Synchronously present a frame with no acknowledgement.
   bool Present(HWND window);
 
+  // Copies the surface data to |buf|. The image data is transformed so that it
+  // fits in |size|.
+  bool CopyTo(const gfx::Size& size, std::vector<unsigned char>* buf);
+
   // Temporarily release resources until a new surface is asynchronously
   // presented. Present will not be able to represent the last surface after
   // calling this and will return false.