cc: Add UMA stats for record and raster time.

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index 1e3c132ab646e4078f458dcc236dfe711f34723b..b98b7a6e6399d528701a1440b6debc9c422f2f00 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -13,6 +13,7 @@
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "cc/base/histograms.h"
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/frame_viewer_instrumentation.h"
 #include "cc/debug/traced_value.h"
@@ -29,6 +30,11 @@ namespace {
 // a tile is of solid color.
 const bool kUseColorEstimator = true;
 
+DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
+    ScopedRasterTaskTimer,
+    "Compositing.RasterTask.RasterUs",
+    "Compositing.RasterTask.RasterPixelsPerMs");
+
 class RasterTaskImpl : public RasterTask {
  public:
   RasterTaskImpl(
@@ -108,6 +114,8 @@ class RasterTaskImpl : public RasterTask {
   void Raster(const RasterSource* raster_source) {
     frame_viewer_instrumentation::ScopedRasterTask raster_task(
         tile_id_, tile_resolution_, source_frame_number_, layer_id_);
+    ScopedRasterTaskTimer timer;
+    timer.SetArea(content_rect_.size().GetArea());
 
     DCHECK(raster_source);