Move scroll event handlers from layer to layer tree view.

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index fe3c1c7048fd91df072f6cd9878739bed61bc5f5..162aca972268005a4db713a5e79309d458423cff 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -503,13 +503,6 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
     return !!main_thread_scrolling_reasons_;
   }
 
-  void SetHaveScrollEventHandlers(bool have_scroll_event_handlers) {
-    have_scroll_event_handlers_ = have_scroll_event_handlers;
-  }
-  bool have_scroll_event_handlers() const {
-    return have_scroll_event_handlers_;
-  }
-
   void SetNonFastScrollableRegion(const Region& region) {
     non_fast_scrollable_region_ = region;
   }
@@ -761,7 +754,6 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
 
   gfx::Vector2dF offset_to_transform_parent_;
   uint32_t main_thread_scrolling_reasons_;
-  bool have_scroll_event_handlers_ : 1;
 
   bool user_scrollable_horizontal_ : 1;
   bool user_scrollable_vertical_ : 1;