cc: Make OutputSurfaceFrame::sub_buffer_rect optional

content/browser/renderer_host/compositor_impl_android.cc

Index: content/browser/renderer_host/compositor_impl_android.cc
diff --git a/content/browser/renderer_host/compositor_impl_android.cc b/content/browser/renderer_host/compositor_impl_android.cc
index 49abcb2ce93af4880932990c093b24aec42ed6a5..eda8fc5da7231c5c2cc89268d1cc214ea5085c14 100644
--- a/content/browser/renderer_host/compositor_impl_android.cc
+++ b/content/browser/renderer_host/compositor_impl_android.cc
@@ -157,10 +157,10 @@ class AndroidOutputSurface : public cc::OutputSurface {
 
   void SwapBuffers(cc::OutputSurfaceFrame frame) override {
     GetCommandBufferProxy()->SetLatencyInfo(frame.latency_info);
-    if (frame.sub_buffer_rect.IsEmpty()) {
+    if (frame.sub_buffer_rect) {
+      DCHECK(frame.sub_buffer_rect->IsEmpty());
       context_provider_->ContextSupport()->CommitOverlayPlanes();
     } else {
-      DCHECK(frame.sub_buffer_rect == gfx::Rect(frame.size));
       context_provider_->ContextSupport()->Swap();
     }
   }