Support copying a partial rectangle region from the compositing surface on Aura and GTK.

content/port/browser/render_widget_host_view_port.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_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_
 #define CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_
 
 #include "base/callback.h"
 #include "base/process_util.h"
 #include "base/string16.h"
@@ skipping 126 matching lines @@
   // |start_rect| and |end_rect| are the bounds end of the selection in the
   // coordinate system of the render view.
   virtual void SelectionBoundsChanged(const gfx::Rect& start_rect,
                                       const gfx::Rect& end_rect) {}
 
   // Allocate a backing store for this view.
   virtual BackingStore* AllocBackingStore(const gfx::Size& size) = 0;
 
   // Copies the contents of the compositing surface into the given
   // (uninitialized) PlatformCanvas if any.
+  // The rectangle region specified with |src_subrect| is copied from the
+  // contents, scaled to |dst_size|, and written to |output|.
   // |callback| is invoked with true on success, false otherwise. |output| can
   // be initialized even on failure.
   // NOTE: |callback| is called asynchronously on Aura and synchronously on the
   // other platforms.
   virtual void CopyFromCompositingSurface(
-      const gfx::Size& size,
+      const gfx::Rect& src_subrect,
+      const gfx::Size& dst_size,
       const base::Callback<void(bool)>& callback,
       skia::PlatformCanvas* output) = 0;
 
   // Called when accelerated compositing state changes.
   virtual void OnAcceleratedCompositingStateChange() = 0;
   // |params.window| and |params.surface_id| indicate which accelerated
   // surface's buffers swapped. |params.renderer_id| and |params.route_id|
   // are used to formulate a reply to the GPU process to prevent it from getting
   // too far ahead. They may all be zero, in which case no flow control is
   // enforced; this case is currently used for accelerated plugins.
@@ skipping 98 matching lines @@
   virtual BrowserAccessibilityManager*
       GetBrowserAccessibilityManager() const = 0;
   virtual void OnAccessibilityNotifications(
       const std::vector<AccessibilityHostMsg_NotificationParams>& params) {
   }
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_