cc: Switch RenderingStats collection in Layer::Update() to RenderingStatsInstrumentation

cc/trees/layer_tree_host_unittest_occlusion.cc

Index: cc/trees/layer_tree_host_unittest_occlusion.cc
diff --git a/cc/trees/layer_tree_host_unittest_occlusion.cc b/cc/trees/layer_tree_host_unittest_occlusion.cc
index 72abb153d69220b752be3befa71594ca90762391..b5a6c8b22910593c9cd525f49d17794978b62f1c 100644
--- a/cc/trees/layer_tree_host_unittest_occlusion.cc
+++ b/cc/trees/layer_tree_host_unittest_occlusion.cc
@@ -19,8 +19,7 @@ class TestLayer : public Layer {
 
   virtual void Update(
       ResourceUpdateQueue* update_queue,
-      const OcclusionTracker* occlusion,
-      RenderingStats* stats) OVERRIDE {
+      const OcclusionTracker* occlusion) OVERRIDE {
     if (!occlusion)
       return;