cc: Commit directly to active tree when using single thread.

Skip making a pending tree, we'll want to wait for it anyways before
we draw in single-thread mode. This should bring the single-thread
impl-side painting in line with the legacy compositing mode when
using a single thread (for the browser compositor).

R=enne@chromium.org, vmpstr
BUG=441012

Review URL: https://codereview.chromium.org/873473006

Cr-Commit-Position: refs/heads/master@{#316678}

1 files changed, 1 insertions, 7 deletions

diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index a49c516..3cb2858 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -295,7 +295,7 @@ void LayerTreeHostImpl::BeginCommit() {
   if (!settings_.impl_side_painting && output_surface_)
     output_surface_->ForceReclaimResources();
 
-  if (UsePendingTreeForSync())
+  if (settings_.impl_side_painting && !proxy_->CommitToActiveTree())
     CreatePendingTree();
 }
 
@@ -2072,12 +2072,6 @@ void LayerTreeHostImpl::DestroyTileManager() {
   single_thread_synchronous_task_graph_runner_ = nullptr;
 }
 
-bool LayerTreeHostImpl::UsePendingTreeForSync() const {
-  // In impl-side painting, synchronize to the pending tree so that it has
-  // time to raster before being displayed.
-  return settings_.impl_side_painting;
-}
-
 bool LayerTreeHostImpl::IsSynchronousSingleThreaded() const {
   return !proxy_->HasImplThread() && !settings_.single_thread_proxy_scheduler;
 }