cc: Remove unused metrics from RenderingStats.

cc/trees/single_thread_proxy.cc

Index: cc/trees/single_thread_proxy.cc
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 4e47b33093a8f77ee2b8f55b29b629e0d15c1a01..0c04b5b78e5fda9b66efcbcbeba6969455896797 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -191,10 +191,6 @@ void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
     // to receive its callbacks before that.
     BlockingTaskRunner::CapturePostTasks blocked;
 
-    RenderingStatsInstrumentation* stats_instrumentation =
-        layer_tree_host_->rendering_stats_instrumentation();
-    base::TimeTicks start_time = stats_instrumentation->StartRecording();
-
     layer_tree_host_impl_->BeginCommit();
 
     if (layer_tree_host_->contents_texture_manager()) {
@@ -227,8 +223,8 @@ void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
     DCHECK_EQ(1.f, scroll_info->page_scale_delta);
 #endif
 
-    base::TimeDelta duration = stats_instrumentation->EndRecording(start_time);
-    stats_instrumentation->AddCommit(duration);
+    RenderingStatsInstrumentation* stats_instrumentation =
+        layer_tree_host_->rendering_stats_instrumentation();
     stats_instrumentation->IssueTraceEventForMainThreadStats();
     stats_instrumentation->AccumulateAndClearMainThreadStats();
   }