gpu: Only estimate parent compositor run time when needed

When BeginFrame scheduling is enabled, the browser compositor
automatically adjusts the deadline it passes down to the renderer to
account for its own draw time. Make sure we don't also subtract the
estimated draw time in the renderer.

BUG=359566

Review URL: https://codereview.chromium.org/335873002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277774 0039d316-1c4b-4281-b951-d872f2087c98

cc/trees/layer_tree_host_impl.cc

@@ -2023,7 +2023,8 @@ bool LayerTreeHostImpl::InitializeRenderer(
 
   // TODO(brianderson): Don't use a hard-coded parent draw time.
   base::TimeDelta parent_draw_time =
-      output_surface_->capabilities().adjust_deadline_for_parent
+      (!settings_.begin_frame_scheduling_enabled &&
+       output_surface_->capabilities().adjust_deadline_for_parent)
           ? BeginFrameArgs::DefaultEstimatedParentDrawTime()
           : base::TimeDelta();
   client_->SetEstimatedParentDrawTime(parent_draw_time);