cc: Support animating scroll offset

cc/trees/layer_tree_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_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/base/math_util.h"
@@ skipping 595 matching lines @@
 }
 
 gfx::Size LayerTreeImpl::DrawViewportSize() const {
   return layer_tree_host_impl_->DrawViewportSize();
 }
 
 void LayerTreeImpl::StartScrollbarAnimation() {
   layer_tree_host_impl_->StartScrollbarAnimation();
 }
 
+void LayerTreeImpl::DidAnimateScrollOffset() {
+  layer_tree_host_impl_->DidAnimateScrollOffset();
+}
+
 void LayerTreeImpl::SetNeedsRedraw() {
   layer_tree_host_impl_->SetNeedsRedraw();
 }
 
 const LayerTreeDebugState& LayerTreeImpl::debug_state() const {
   return layer_tree_host_impl_->debug_state();
 }
 
 float LayerTreeImpl::device_scale_factor() const {
   return layer_tree_host_impl_->device_scale_factor();
@@ skipping 151 matching lines @@
 const std::vector<LayerImpl*> LayerTreeImpl::LayersWithCopyOutputRequest()
     const {
   // Only the active tree needs to know about layers with copy requests, as
   // they are aborted if not serviced during draw.
   DCHECK(IsActiveTree());
 
   return layers_with_copy_output_request_;
 }
 
 }  // namespace cc