cc: Use HighResNow as timebase if it is fast and reliable

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 38 matching lines @@
 #include "cc/resources/ui_resource_bitmap.h"
 #include "cc/scheduler/delay_based_time_source.h"
 #include "cc/scheduler/texture_uploader.h"
 #include "cc/trees/damage_tracker.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/quad_culler.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/tree_synchronizer.h"
+#include "ui/gfx/frame_time.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/vector2d_conversions.h"
 
 namespace {
 
 void DidVisibilityChange(cc::LayerTreeHostImpl* id, bool visible) {
   if (visible) {
     TRACE_EVENT_ASYNC_BEGIN1("webkit",
                              "LayerTreeHostImpl::SetVisible",
                              id,
@@ skipping 2605 matching lines @@
   UpdateCurrentFrameTime(&current_frame_timeticks_, &current_frame_time_);
   return current_frame_timeticks_;
 }
 
 base::Time LayerTreeHostImpl::CurrentFrameTime() {
   UpdateCurrentFrameTime(&current_frame_timeticks_, &current_frame_time_);
   return current_frame_time_;
 }
 
 base::TimeTicks LayerTreeHostImpl::CurrentPhysicalTimeTicks() const {
-  return base::TimeTicks::Now();
+  return gfx::FrameTime::Now();
 }
 
 scoped_ptr<base::Value> LayerTreeHostImpl::AsValueWithFrame(
     FrameData* frame) const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   if (this->pending_tree_)
       state->Set("activation_state", ActivationStateAsValue().release());
   state->Set("device_viewport_size",
              MathUtil::AsValue(device_viewport_size_).release());
   if (tile_manager_)
@@ skipping 109 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