cc: Save correct frame begin time to FrameRateCounter

cc/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/layer_tree_host_impl.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
@@ skipping 912 matching lines @@
 
   if (!RootScrollLayer())
     return metadata;
 
   metadata.root_scroll_offset = RootScrollLayer()->scroll_offset() +
                                 RootScrollLayer()->scroll_delta();
 
   return metadata;
 }
 
-void LayerTreeHostImpl::DrawLayers(FrameData* frame) {
+void LayerTreeHostImpl::DrawLayers(FrameData* frame,
+                                   base::TimeTicks frame_begin_time) {
   TRACE_EVENT0("cc", "LayerTreeHostImpl::DrawLayers");
   DCHECK(CanDraw());
   DCHECK(!frame->render_passes.empty());
 
-  // FIXME: use the frame begin time from the overall compositor scheduler.
-  // This value is currently inaccessible because it is up in Chromium's
-  // RenderWidget.
-  fps_counter_->saveTimeStamp(base::TimeTicks::Now());
+  fps_counter_->saveTimeStamp(frame_begin_time);
 
   if (tile_manager_) {
     memory_history_->SaveEntry(
         tile_manager_->memory_stats_from_last_assign());
   }
 
   if (debug_state_.showHudRects()) {
     debug_rect_history_->SaveDebugRectsForCurrentFrame(
         active_tree_->root_layer(),
         *frame->render_surface_layer_list,
@@ skipping 970 matching lines @@
     tile_manager_->SetRecordRenderingStats(debug_state_.recordRenderingStats());
 }
 
 void LayerTreeHostImpl::SavePaintTime(const base::TimeDelta& total_paint_time,
                                       int commit_number) {
   DCHECK(debug_state_.continuousPainting);
   paint_time_counter_->SavePaintTime(total_paint_time, commit_number);
 }
 
 }  // namespace cc