UMA metrics for use count of wheel and touch scrolls.

cc/trees/layer_tree_host_common.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_common.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 162 matching lines @@
 LayerTreeHostCommon::ScrollbarsUpdateInfo::ScrollbarsUpdateInfo(int layer_id,
                                                                 bool hidden)
     : layer_id(layer_id), hidden(hidden) {}
 
 bool LayerTreeHostCommon::ScrollbarsUpdateInfo::operator==(
     const LayerTreeHostCommon::ScrollbarsUpdateInfo& other) const {
   return layer_id == other.layer_id && hidden == other.hidden;
 }
 
 ScrollAndScaleSet::ScrollAndScaleSet()
-    : page_scale_delta(1.f), top_controls_delta(0.f) {
-}
+    : page_scale_delta(1.f),
+      top_controls_delta(0.f),
+      has_scrolled_by_wheel(false),
+      has_scrolled_by_touch(false) {}
 
 ScrollAndScaleSet::~ScrollAndScaleSet() {}
 
 static inline void SetMaskLayersAreDrawnRenderSurfaceLayerListMembers(
     RenderSurfaceImpl* surface,
     PropertyTrees* property_trees) {
   LayerImpl* mask_layer = surface->MaskLayer();
   if (mask_layer) {
     mask_layer->set_is_drawn_render_surface_layer_list_member(true);
     draw_property_utils::ComputeMaskDrawProperties(mask_layer, property_trees);
@@ skipping 449 matching lines @@
 
 PropertyTrees* GetPropertyTrees(Layer* layer) {
   return layer->layer_tree_host()->property_trees();
 }
 
 PropertyTrees* GetPropertyTrees(LayerImpl* layer) {
   return layer->layer_tree_impl()->property_trees();
 }
 
 }  // namespace cc