Mac: Enable partial swap

content/common/gpu/image_transport_surface_overlay_mac.h

 // Copyright 2015 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_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_OVERLAY_MAC_H_
 #define CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_OVERLAY_MAC_H_
 
 #include <deque>
 
 #include "base/memory/linked_ptr.h"
@@ skipping 61 matching lines @@
   // another SwapBuffers happens before this callback, the pending swap will
   // be tested at that time, too.
   void CheckPendingSwapsCallback();
   // Function to post the above callback. The argument |now| is passed as an
   // argument to avoid redundant calls to base::TimeTicks::Now.
   void PostCheckPendingSwapsCallbackIfNeeded(const base::TimeTicks& now);
 
   scoped_ptr<ImageTransportHelper> helper_;
   base::scoped_nsobject<CAContext> ca_context_;
   base::scoped_nsobject<CALayer> layer_;
+  base::scoped_nsobject<CALayer> partial_damage_layer_;
 
   gfx::Size pixel_size_;
   float scale_factor_;
   std::vector<ui::LatencyInfo> latency_info_;
 
   // Weak pointer to the image provided when ScheduleOverlayPlane is called. Is
   // consumed and reset when SwapBuffers is called. For now, only one overlay
   // plane is supported.
   gfx::GLImage* pending_overlay_image_;
 
   // A queue of all frames that have been created by SwapBuffersInternal but
   // have not yet been displayed. This queue is checked at the beginning of
   // every swap and also by a callback.
   std::deque<linked_ptr<PendingSwap>> pending_swaps_;
 
+  // The union of the damage rects of SwapBuffersInternal since the last
+  // non-partial swap.
+  gfx::Rect accumulated_partial_damage_pixel_rect_;
+
   // The display link used to compute the time for callbacks.
   scoped_refptr<ui::DisplayLinkMac> display_link_mac_;
 
   // True if there is a pending call to CheckPendingSwapsCallback posted.
   bool has_pending_callback_;
 
   base::WeakPtrFactory<ImageTransportSurfaceOverlayMac> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_OVERLAY_MAC_H_