Fix race conditions in window snapshot code.

cc/trees/layer_tree_host.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.h"
 
 #include <algorithm>
 #include <stack>
 
 #include "base/bind.h"
@@ skipping 504 matching lines @@
 }
 
 bool LayerTreeHost::CommitRequested() const {
   return proxy_->CommitRequested();
 }
 
 void LayerTreeHost::SetNextCommitWaitsForActivation() {
   proxy_->SetNextCommitWaitsForActivation();
 }
 
+void LayerTreeHost::SetNextCommitForcesRedraw() {
+  proxy_->SetNextCommitForcesRedraw();
+}
+
 void LayerTreeHost::SetAnimationEvents(scoped_ptr<AnimationEventsVector> events,
                                        base::Time wall_clock_time) {
   DCHECK(proxy_->IsMainThread());
   for (size_t event_index = 0; event_index < events->size(); ++event_index) {
     int event_layer_id = (*events)[event_index].layer_id;
 
     // Use the map of all controllers, not just active ones, since non-active
     // controllers may still receive events for impl-only animations.
     const AnimationRegistrar::AnimationControllerMap& animation_controllers =
         animation_registrar_->all_animation_controllers();
@@ skipping 632 matching lines @@
 void LayerTreeHost::DidLoseUIResources() {
   // When output surface is lost, we need to recreate the resource.
   for (UIResourceClientMap::iterator iter = ui_resource_client_map_.begin();
        iter != ui_resource_client_map_.end();
        ++iter) {
     UIResourceLost(iter->first);
   }
 }
 
 }  // namespace cc