Support copying a partial rectangle region from the compositing surface on Win.

ui/surface/accelerated_surface_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 UI_SURFACE_ACCELERATED_SURFACE_WIN_H_
 #define UI_SURFACE_ACCELERATED_SURFACE_WIN_H_
 
 #include <d3d9.h>
 
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/win/scoped_comptr.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 #include "ui/surface/surface_export.h"
 
 class PresentThread;
 
+namespace gfx {
+class Rect;
+}
+
 class SURFACE_EXPORT AcceleratedPresenter
     : public base::RefCountedThreadSafe<AcceleratedPresenter> {
  public:
   typedef base::Callback<void(bool)> CompletionTaskl;
 
   explicit AcceleratedPresenter(gfx::NativeWindow window);
 
   // Returns a thread safe reference to the presenter for the given window or
   // null is no such presenter exists. The thread safe refptr ensures the
   // presenter will not be destroyed. This can be called on any thread.
@@ skipping 14 matching lines @@
   void Suspend();
 
   // Indicates that the presenter has become invisible.
   void WasHidden();
 
   // Schedule the presenter to release its reference to the shared surface.
   void ReleaseSurface();
 
   // The public member functions are called on the main thread.
   bool Present(HDC dc);
-  bool CopyTo(const gfx::Size& size, void* buf);
+  bool CopyTo(const gfx::Rect& src_subrect,
+              const gfx::Size& dst_size,
+              void* buf);
   void Invalidate();
 
  private:
   friend class base::RefCountedThreadSafe<AcceleratedPresenter>;
 
   ~AcceleratedPresenter();
 
   // These member functions are called on the PresentThread with which the
   // presenter has affinity.
   void DoPresentAndAcknowledge(
@@ skipping 42 matching lines @@
 };
 
 class SURFACE_EXPORT AcceleratedSurface {
  public:
   AcceleratedSurface(gfx::NativeWindow window);
   ~AcceleratedSurface();
 
   // Synchronously present a frame with no acknowledgement.
   bool Present(HDC dc);
 
-  // Copies the surface data to |buf|. The image data is transformed so that it
-  // fits in |size|.
+  // Copies the surface data to |buf|. The copied region is specified with
+  // |src_subrect| and the image data is transformed so that it fits in
+  // |dst_size|.
   // Caller must ensure that |buf| is allocated with the size no less than
-  // |4 * size.width() * size.height()| bytes.
-  bool CopyTo(const gfx::Size& size, void* buf);
+  // |4 * dst_size.width() * dst_size.height()| bytes.
+  bool CopyTo(const gfx::Rect& src_subrect,
+              const gfx::Size& dst_size,
+              void* 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.
   void Suspend();
 
   // Indicates that the surface has become invisible.
   void WasHidden();
 
  private:
   const scoped_refptr<AcceleratedPresenter> presenter_;
   DISALLOW_COPY_AND_ASSIGN(AcceleratedSurface);
 };
 
 #endif  // UI_SURFACE_ACCELERATED_SURFACE_WIN_H_