cc: Block commit on activate by setting a flag on LayerTreeHost.

cc/trees/thread_proxy.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/thread_proxy.h"
 
 #include <string>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 905 matching lines @@
   DCHECK(IsImplThread());
   DCHECK(commit_completion_event_on_impl_thread_);
   DCHECK(current_resource_update_controller_on_impl_thread_);
 
   // Complete all remaining texture updates.
   current_resource_update_controller_on_impl_thread_->Finalize();
   current_resource_update_controller_on_impl_thread_.reset();
 
   layer_tree_host_impl_->BeginCommit();
   layer_tree_host_->BeginCommitOnImplThread(layer_tree_host_impl_.get());
+  bool commit_waits_for_activation =
+      layer_tree_host_->CommitWaitsForActivation();
   layer_tree_host_->FinishCommitOnImplThread(layer_tree_host_impl_.get());
   layer_tree_host_impl_->CommitComplete();
 
   SetInputThrottledUntilCommitOnImplThread(false);
 
   layer_tree_host_impl_->UpdateBackgroundAnimateTicking(
       !scheduler_on_impl_thread_->WillDrawIfNeeded());
 
   next_frame_is_newly_committed_frame_on_impl_thread_ = true;
 
   if (layer_tree_host_->settings().impl_side_painting &&
-      layer_tree_host_->BlocksPendingCommit() &&
-      layer_tree_host_impl_->pending_tree()) {
+      commit_waits_for_activation) {
     // For some layer types in impl-side painting, the commit is held until
     // the pending tree is activated.  It's also possible that the
     // pending tree has already activated if there was no work to be done.
     TRACE_EVENT_INSTANT0("cc", "HoldCommit", TRACE_EVENT_SCOPE_THREAD);
     completion_event_for_commit_held_on_tree_activation_ =
         commit_completion_event_on_impl_thread_;
     commit_completion_event_on_impl_thread_ = NULL;
   } else {
     commit_completion_event_on_impl_thread_->Signal();
     commit_completion_event_on_impl_thread_ = NULL;
@@ skipping 561 matching lines @@
     DCHECK(layer_tree_host_impl_->settings().impl_side_painting);
     completion_event_for_commit_held_on_tree_activation_->Signal();
     completion_event_for_commit_held_on_tree_activation_ = NULL;
   }
 
   commit_to_activate_duration_history_.InsertSample(
       base::TimeTicks::HighResNow() - commit_complete_time_);
 }
 
 }  // namespace cc