Reland: Refactor unreliable hit test code to avoid owning_layers

cc/layers/layer_impl.h

 // 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.
 
 #ifndef CC_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 376 matching lines @@
       std::unique_ptr<base::trace_event::ConvertableToTraceFormat> debug_info);
 
   void set_is_drawn_render_surface_layer_list_member(bool is_member) {
     is_drawn_render_surface_layer_list_member_ = is_member;
   }
 
   bool is_drawn_render_surface_layer_list_member() const {
     return is_drawn_render_surface_layer_list_member_;
   }
 
+  bool IsDrawnScrollbar() {
+    return ToScrollbarLayer() && is_drawn_render_surface_layer_list_member_;
+  }
+
   void set_may_contain_video(bool yes) { may_contain_video_ = yes; }
   bool may_contain_video() const { return may_contain_video_; }
 
   // Layers that share a sorting context id will be sorted together in 3d
   // space.  0 is a special value that means this layer will not be sorted and
   // will be drawn in paint order.
   int GetSortingContextId() const;
 
   // Get the correct invalidation region instead of conservative Rect
   // for layers that provide it.
@@ skipping 159 matching lines @@
   bool has_will_change_transform_hint_ : 1;
   bool needs_push_properties_ : 1;
   bool scrollbars_hidden_ : 1;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_