Limit outstanding surface draw swaps to max_frames_pending.

cc/surfaces/display.cc

Index: cc/surfaces/display.cc
diff --git a/cc/surfaces/display.cc b/cc/surfaces/display.cc
index 105eeb2e3d46f6a64ed3c2ecd443c4ef52523f8b..cd067689a8e42557935208a48af036ac754dafb0 100644
--- a/cc/surfaces/display.cc
+++ b/cc/surfaces/display.cc
@@ -132,6 +132,14 @@ bool Display::Draw() {
   return true;
 }
 
+void Display::DidSwapBuffers() {
+  client_->DidSwapBuffers();
+}
+
+void Display::DidSwapBuffersComplete() {
+  client_->DidSwapBuffersComplete();
+}
+
 void Display::OnSurfaceDamaged(SurfaceId surface) {
   if (aggregator_ && aggregator_->previous_contained_surfaces().count(surface))
     client_->DisplayDamaged();
@@ -141,4 +149,10 @@ SurfaceId Display::CurrentSurfaceId() {
   return current_surface_id_;
 }
 
+int Display::GetMaxFramesPending() {
+  if (!output_surface_)
+    return OutputSurface::DEFAULT_MAX_FRAMES_PENDING;
+  return output_surface_->capabilities().max_frames_pending;
+}
+
 }  // namespace cc