[DRAFT] Animations: Profile hash look-ups for external mutators

cc/trees/layer_tree_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_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
+#include "base/metrics/histogram.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/animation/animation_host.h"
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/animation/scrollbar_animation_controller_linear_fade.h"
 #include "cc/animation/scrollbar_animation_controller_thinning.h"
 #include "cc/base/math_util.h"
 #include "cc/base/synced_property.h"
 #include "cc/debug/devtools_instrumentation.h"
@@ skipping 697 matching lines @@
 gfx::Size LayerTreeImpl::ScrollableSize() const {
   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
                                      ? OuterViewportScrollLayer()
                                      : InnerViewportScrollLayer();
   if (!root_scroll_layer || root_scroll_layer->children().empty())
     return gfx::Size();
   return root_scroll_layer->children()[0]->bounds();
 }
 
 LayerImpl* LayerTreeImpl::LayerById(int id) const {
+  base::TimeTicks start_time = base::TimeTicks::Now();
   LayerIdMap::const_iterator iter = layer_id_map_.find(id);
+  find_layer_by_id_stats_ += base::TimeTicks::Now() - start_time;
   return iter != layer_id_map_.end() ? iter->second : NULL;
 }
 
 void LayerTreeImpl::RegisterLayer(LayerImpl* layer) {
   DCHECK(!LayerById(layer->id()));
   layer_id_map_[layer->id()] = layer;
   if (layer_tree_host_impl_->animation_host())
     layer_tree_host_impl_->animation_host()->RegisterLayer(layer->id(),
                                                            IsActiveTree());
 }
 
 void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
   DCHECK(LayerById(layer->id()));
   if (layer_tree_host_impl_->animation_host())
     layer_tree_host_impl_->animation_host()->UnregisterLayer(layer->id(),
                                                              IsActiveTree());
   layer_id_map_.erase(layer->id());
 }
 
+void LayerTreeImpl::ClearStatsOnFrameEnd() {
+  find_layer_by_id_stats_ = base::TimeDelta();
+}
+
 size_t LayerTreeImpl::NumLayers() {
   return layer_id_map_.size();
 }
 
 void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
   pending_tree->SetCurrentlyScrollingLayer(
       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
           currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
 }
 
@@ skipping 966 matching lines @@
                                                    const gfx::BoxF& box,
                                                    gfx::BoxF* bounds) const {
   *bounds = gfx::BoxF();
   return layer_tree_host_impl_->animation_host()
              ? layer_tree_host_impl_->animation_host()
                    ->TransformAnimationBoundsForBox(layer->id(), box, bounds)
              : true;
 }
 
 }  // namespace cc