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

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 280 matching lines @@
 
 void LayerTreeHostImpl::BeginCommit() {
   TRACE_EVENT0("cc", "LayerTreeHostImpl::BeginCommit");
 
   // Ensure all textures are returned so partial texture updates can happen
   // during the commit. Impl-side-painting doesn't upload during commits, so
   // is unaffected.
   if (!settings_.impl_side_painting && output_surface_)
     output_surface_->ForceReclaimResources();
 
-  if (UsePendingTreeForSync())
+  if (settings_.impl_side_painting && !proxy_->CommitToActiveTree())
     CreatePendingTree();
 }
 
 void LayerTreeHostImpl::CommitComplete() {
   TRACE_EVENT0("cc", "LayerTreeHostImpl::CommitComplete");
 
   if (pending_tree_)
     pending_tree_->ApplyScrollDeltasSinceBeginMainFrame();
   sync_tree()->set_needs_update_draw_properties();
 
@@ skipping 1734 matching lines @@
 
 void LayerTreeHostImpl::DestroyTileManager() {
   tile_manager_ = nullptr;
   resource_pool_ = nullptr;
   staging_resource_pool_ = nullptr;
   tile_task_worker_pool_ = nullptr;
   rasterizer_ = nullptr;
   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;
 }
 
 void LayerTreeHostImpl::EnforceZeroBudget(bool zero_budget) {
   SetManagedMemoryPolicy(cached_managed_memory_policy_, zero_budget);
 }
 
 bool LayerTreeHostImpl::InitializeRenderer(
     scoped_ptr<OutputSurface> output_surface) {
@@ skipping 1382 matching lines @@
 }
 
 void LayerTreeHostImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
   std::vector<PictureLayerImpl*>::iterator it =
       std::find(picture_layers_.begin(), picture_layers_.end(), layer);
   DCHECK(it != picture_layers_.end());
   picture_layers_.erase(it);
 }
 
 }  // namespace cc