Support browser side thumbnailing for GPU composited pages on Windows.

content/browser/gpu/gpu_surface_reader_win.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_BROWSER_GPU_GPU_SURFACE_READER_WIN_H_
+#define CONTENT_BROWSER_GPU_GPU_SURFACE_READER_WIN_H_
+
+#include <vector>
+#include "content/browser/gpu/gpu_surface_tracker.h"
+#include "ui/gfx/size.h"
+
+class GpuSurfaceReader {

[apatrick_chromium, 2012/03/07 20:39:37]

Do you envision this class ever having state? I don't see why CopySurface is not
just a free function.

[mazda, 2012/03/08 13:14:28]

I thought it might be useful to be able to switch the implementation easily. 
Now I moved the code to RenderWidgetHostViewWin

+ public:
+  GpuSurfaceReader();
+  virtual ~GpuSurfaceReader();
+
+  // Copies the image data of the the given surface to |out|. The image data
+  // is transformed so that it fits in |size|.
+  bool CopySurface(const GpuSurfaceTracker::SurfaceInfo& surface_info,
+                   const gfx::Size& size,
+                   std::vector<unsigned char>* out);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(GpuSurfaceReader);
+};
+
+#endif  // CONTENT_BROWSER_GPU_GPU_SURFACE_READER_WIN_H_