cc: Fix touch hit-testing for overlapping layers.

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 417 matching lines @@
 
 bool LayerTreeHostImpl::HaveTouchEventHandlersAt(gfx::Point viewport_point) {
   if (!settings_.touch_hit_testing)
     return true;
   if (!EnsureRenderSurfaceLayerList())
     return false;
 
   gfx::PointF device_viewport_point =
       gfx::ScalePoint(viewport_point, device_scale_factor_);
 
-  // First find out which layer was hit from the saved list of visible layers
-  // in the most recent frame.
-  LayerImpl* layer_impl = LayerTreeHostCommon::FindLayerThatIsHitByPoint(
-      device_viewport_point,
-      active_tree_->RenderSurfaceLayerList());
-
-  // Walk up the hierarchy and look for a layer with a touch event handler
-  // region that the given point hits.
-  for (; layer_impl; layer_impl = layer_impl->parent()) {
-    if (LayerTreeHostCommon::LayerHasTouchEventHandlersAt(device_viewport_point,
-                                                          layer_impl))
-      return true;
-  }
-
-  return false;
+  LayerImpl* layer_impl =
+      LayerTreeHostCommon::FindLayerThatIsHitByPointInTouchHandlerRegion(
+          device_viewport_point,
+          active_tree_->RenderSurfaceLayerList());
+  return layer_impl != NULL;
 }
 
 void LayerTreeHostImpl::SetLatencyInfoForInputEvent(
     const ui::LatencyInfo& latency_info) {
   active_tree()->SetLatencyInfo(latency_info);
 }
 
 void LayerTreeHostImpl::TrackDamageForAllSurfaces(
     LayerImpl* root_draw_layer,
     const LayerImplList& render_surface_layer_list) {
@@ skipping 2345 matching lines @@
   std::set<UIResourceId>::iterator found_in_evicted =
       evicted_ui_resources_.find(uid);
   if (found_in_evicted == evicted_ui_resources_.end())
     return;
   evicted_ui_resources_.erase(found_in_evicted);
   if (evicted_ui_resources_.empty())
     client_->OnCanDrawStateChanged(CanDraw());
 }
 
 }  // namespace cc