cc: Make OutputSurfaceFrame::sub_buffer_rect optional

services/ui/surfaces/display_output_surface.cc

 // 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 "services/ui/surfaces/display_output_surface.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
@@ skipping 47 matching lines @@
                                    float device_scale_factor,
                                    const gfx::ColorSpace& color_space,
                                    bool has_alpha,
                                    bool use_stencil) {
   context_provider()->ContextGL()->ResizeCHROMIUM(
       size.width(), size.height(), device_scale_factor, has_alpha);
 }
 
 void DisplayOutputSurface::SwapBuffers(cc::OutputSurfaceFrame frame) {
   DCHECK(context_provider_);
-  if (frame.sub_buffer_rect == gfx::Rect(frame.size)) {
+  if (frame.sub_buffer_rect) {
+    context_provider_->ContextSupport()->PartialSwapBuffers(
+        *frame.sub_buffer_rect);
+  } else {
     context_provider_->ContextSupport()->Swap();
-  } else {
-    context_provider_->ContextSupport()->PartialSwapBuffers(
-        frame.sub_buffer_rect);
   }
 }
 
 uint32_t DisplayOutputSurface::GetFramebufferCopyTextureFormat() {
   // TODO(danakj): What attributes are used for the default framebuffer here?
   // Can it have alpha? cc::InProcessContextProvider doesn't take any
   // attributes.
   return GL_RGB;
 }
 
@@ skipping 33 matching lines @@
 
 void DisplayOutputSurface::OnVSyncParametersUpdated(base::TimeTicks timebase,
                                                     base::TimeDelta interval) {
   // TODO(brianderson): We should not be receiving 0 intervals.
   synthetic_begin_frame_source_->OnUpdateVSyncParameters(
       timebase,
       interval.is_zero() ? cc::BeginFrameArgs::DefaultInterval() : interval);
 }
 
 }  // namespace ui