cc: Support animating scroll offset

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 918 matching lines @@
         this,
         DelayBasedTimeSource::Create(
             LowFrequencyAnimationInterval(),
             proxy_->HasImplThread() ? proxy_->ImplThreadTaskRunner()
                                     : proxy_->MainThreadTaskRunner()));
   }
 
   time_source_client_adapter_->SetActive(enabled);
 }
 
+void LayerTreeHostImpl::DidAnimateScrollOffset() {
+  client_->SetNeedsCommitOnImplThread();
+  client_->RenewTreePriority();
+}
+
 void LayerTreeHostImpl::SetViewportDamage(gfx::Rect damage_rect) {
   viewport_damage_rect_.Union(damage_rect);
 }
 
 static inline RenderPass* FindRenderPassById(
     RenderPass::Id render_pass_id,
     const LayerTreeHostImpl::FrameData& frame) {
   RenderPassIdHashMap::const_iterator it =
       frame.render_passes_by_id.find(render_pass_id);
   return it != frame.render_passes_by_id.end() ? it->second : NULL;
@@ skipping 1912 matching lines @@
   if (evicted_ui_resources_.empty())
     client_->OnCanDrawStateChanged(CanDraw());
 }
 
 void LayerTreeHostImpl::ScheduleMicroBenchmark(
     scoped_ptr<MicroBenchmarkImpl> benchmark) {
   micro_benchmark_controller_.ScheduleRun(benchmark.Pass());
 }
 
 }  // namespace cc