Notify main-thread of top controls state changes

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 917 matching lines @@
 
   // Should only have one render pass in resourceless software mode.
   DCHECK(draw_mode != DRAW_MODE_RESOURCELESS_SOFTWARE ||
          frame->render_passes.size() == 1u)
       << frame->render_passes.size();
 
   return draw_result;
 }
 
 void LayerTreeHostImpl::MainThreadHasStoppedFlinging() {
+  ScrollEnd();

[aelias_OOO_until_Jul13, 2015/02/12 00:45:29]

Not sure we want the "ClearCurrentlyScrollingLayer();" behavior of ScrollEnd. 
There could also be other things added there later that are also incompatible
with main-thread flings -- there's a strong expectation that ScrollEnd matches
ScrollBegin.  I'd suggest adding a new method
TopControlsManager::MainThreadHasStoppedFlinging that just calls
StartAnimationIfNecessary.

[majidvp, 2015/02/12 13:51:48]

Acknowledged.

   if (input_handler_client_)
     input_handler_client_->MainThreadHasStoppedFlinging();
 }
 
 void LayerTreeHostImpl::DidAnimateScrollOffset() {
   client_->SetNeedsCommitOnImplThread();
   client_->RenewTreePriority();
 }
 
 void LayerTreeHostImpl::SetViewportDamage(const gfx::Rect& damage_rect) {
@@ skipping 2553 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