Mac: Partially enable partial swap

content/common/gpu/image_transport_surface_calayer_mac.mm

 // Copyright 2014 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.
 
 #include "content/common/gpu/image_transport_surface_calayer_mac.h"
 
 #include <OpenGL/CGLRenderers.h>
 
 #include "base/command_line.h"
 #include "base/mac/sdk_forward_declarations.h"
@@ skipping 272 matching lines @@
   [layer_ resetStorageProvider];
   layer_.reset();
 
   share_group_context_.reset();
   share_group_context_dirtied_callback_ = base::Closure();
   fbo_texture_ = 0;
   fbo_pixel_size_ = gfx::Size();
   can_draw_returned_false_count_ = 0;
 }
 
-void CALayerStorageProvider::SwapBuffers(
-    const gfx::Size& size, float scale_factor) {
+void CALayerStorageProvider::FrameSizeChanged(const gfx::Size& pixel_size,
+                                              float scale_factor) {
+  DCHECK_EQ(fbo_pixel_size_.ToString(), pixel_size.ToString());
+  DCHECK_EQ(fbo_scale_factor_, scale_factor);
+}
+
+void CALayerStorageProvider::SwapBuffers() {
   DCHECK(!has_pending_draw_);
 
   // Recreate the CALayer on the new GPU if a GPU switch has occurred. Note
   // that the CAContext will retain a reference to the old CALayer until the
   // call to -[CAContext setLayer:] replaces the old CALayer with the new one.
   if (recreate_layer_after_gpu_switch_) {
     [layer_ resetStorageProvider];
     layer_.reset();
     recreate_layer_after_gpu_switch_ = false;
   }
@@ skipping 236 matching lines @@
     return;
   pending_draw_weak_factory_.InvalidateWeakPtrs();
   has_pending_draw_ = false;
   transport_surface_->SendSwapBuffers(
       ui::SurfaceHandleFromCAContextID([context_ contextId]),
       fbo_pixel_size_,
       fbo_scale_factor_);
 }
 
 }  //  namespace content