cc: Add UMA stats for record and raster time.

cc/resources/picture_pile.cc

Index: cc/resources/picture_pile.cc
diff --git a/cc/resources/picture_pile.cc b/cc/resources/picture_pile.cc
index 2ce3e500f2ea86458054ed71b8854a096fff5328..d82ead7b2b772aca24621ea1781b0a07cb4da102 100644
--- a/cc/resources/picture_pile.cc
+++ b/cc/resources/picture_pile.cc
@@ -8,6 +8,7 @@
 #include <limits>
 #include <vector>
 
+#include "cc/base/histograms.h"
 #include "cc/base/region.h"
 #include "cc/resources/picture_pile_impl.h"
 #include "skia/ext/analysis_canvas.h"
@@ -149,6 +150,11 @@ const bool kDefaultClearCanvasSetting = false;
 const bool kDefaultClearCanvasSetting = true;
 #endif
 
+DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
+    ScopedPicturePileUpdateTimer,
+    "Compositing.PicturePile.UpdateUs",
+    "Compositing.PicturePile.UpdateInvalidatedAreaPerMs");
+
 }  // namespace
 
 namespace cc {
@@ -181,6 +187,8 @@ bool PicturePile::UpdateAndExpandInvalidation(
     const gfx::Rect& visible_layer_rect,
     int frame_number,
     RecordingSource::RecordingMode recording_mode) {
+  ScopedPicturePileUpdateTimer timer;
+
   gfx::Rect interest_rect = visible_layer_rect;
   interest_rect.Inset(-pixel_record_distance_, -pixel_record_distance_);
   recorded_viewport_ = interest_rect;
@@ -188,6 +196,13 @@ bool PicturePile::UpdateAndExpandInvalidation(
 
   bool updated = ApplyInvalidationAndResize(interest_rect, invalidation,
                                             layer_size, frame_number);
+
+  // Count the area that is being invalidated.
+  Region recorded_invalidation(*invalidation);
+  recorded_invalidation.Intersect(recorded_viewport_);
+  for (Region::Iterator it(recorded_invalidation); it.has_rect(); it.next())
+    timer.AddArea(it.rect().size().GetArea());
+
   std::vector<gfx::Rect> invalid_tiles;
   GetInvalidTileRects(interest_rect, &invalid_tiles);
   std::vector<gfx::Rect> record_rects;