Add picture pile raster times histogram

cc/tile_manager.cc

 // Copyright 2012 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/tile_manager.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "cc/platform_color.h"
 #include "cc/raster_worker_pool.h"
 #include "cc/resource_pool.h"
 #include "cc/tile.h"
 #include "third_party/skia/include/core/SkDevice.h"
 
 namespace cc {
 
 namespace {
 
@@ skipping 732 matching lines @@
                                 PicturePileImpl* picture_pile,
                                 RenderingStats* stats) {
   TRACE_EVENT0("cc", "TileManager::RunRasterTask");
   DCHECK(picture_pile);
   DCHECK(buffer);
   SkBitmap bitmap;
   bitmap.setConfig(SkBitmap::kARGB_8888_Config, rect.width(), rect.height());
   bitmap.setPixels(buffer);
   SkDevice device(bitmap);
   SkCanvas canvas(&device);
+
+  base::TimeTicks begin_time;
+  if (stats)
+    begin_time = base::TimeTicks::Now();
+
   picture_pile->Raster(&canvas, rect, contents_scale, stats);
+
+  if (stats) {
+    base::TimeTicks end_time = base::TimeTicks::Now();
+    base::TimeDelta duration = end_time - begin_time;

[danakj, 2013/02/04 18:56:24]

nit: i think i'd drop the "duration" variable, I dont think it's adding much
here, and just put end_time-begin_time on the line below.

+    stats->totalRasterizeTime += duration;
+    UMA_HISTOGRAM_CUSTOM_COUNTS(
+      "Renderer4.PictureRasterTimeMS",
+      duration.InMilliseconds(),
+      0, 10, 10
+    );
+  }
 }
 
 // static
 void TileManager::RunImageDecodeTask(skia::LazyPixelRef* pixel_ref,
                                      RenderingStats* stats) {
   TRACE_EVENT0("cc", "TileManager::RunImageDecodeTask");
   base::TimeTicks decode_begin_time;
   if (stats)
     decode_begin_time = base::TimeTicks::Now();
   pixel_ref->Decode();
   if (stats) {
     stats->totalDeferredImageDecodeCount++;
     stats->totalDeferredImageDecodeTime +=
         base::TimeTicks::Now() - decode_begin_time;
   }
 }
 
 }  // namespace cc