Split up software and gpu raster time UMA stats

cc/tiles/tile_manager.cc

Index: cc/tiles/tile_manager.cc
diff --git a/cc/tiles/tile_manager.cc b/cc/tiles/tile_manager.cc
index ea9b32c3523f664ec2576a7b1bce47bb939ef247..9ce43eec2b1a6876e106925b0ab59b974b605e23 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -18,6 +18,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram.h"
 #include "base/numerics/safe_conversions.h"
+#include "base/optional.h"
 #include "base/threading/thread_checker.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/base/histograms.h"
@@ -37,11 +38,46 @@ namespace {
 // a tile is of solid color.
 const bool kUseColorEstimator = true;
 
+// TODO(enne): remove this histogram and its monitoring once there is enough new
+// data from the other two raster task timers.

[Ilya Sherman, 2016/10/03 20:59:11]

nit: Mebbe provide a rough milestone target?

 DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
-    ScopedRasterTaskTimer,
+    ScopedGeneralRasterTaskTimer,
     "Compositing.%s.RasterTask.RasterUs",
     "Compositing.%s.RasterTask.RasterPixelsPerMs");
 
+DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
+    ScopedSoftwareRasterTaskTimer,
+    "Compositing.%s.RasterTask.SoftwareRasterUs",
+    "Compositing.%s.RasterTask.SoftwareRasterPixelsPerMs");

[Ilya Sherman, 2016/10/03 20:59:11]

Optional nit: You might want to name these as "RasterUs.Software", etc., so that
"RasterUs.Software" and "RasterUs.Gpu" end up sorted next to each other.  Also,
if you don't like this suggestion, you might still want to separate "Software"
and "RasterUs" with a dot.

+
+DEFINE_SCOPED_UMA_HISTOGRAM_AREA_TIMER(
+    ScopedGpuRasterTaskTimer,
+    "Compositing.%s.RasterTask.GpuRasterUs",
+    "Compositing.%s.RasterTask.GpuRasterPixelsPerMs");
+
+class ScopedRasterTaskTimer {
+ public:
+  explicit ScopedRasterTaskTimer(bool use_gpu_rasterization) {
+    if (use_gpu_rasterization)
+      gpu_timer_.emplace();
+    else
+      software_timer_.emplace();
+  }
+
+  void SetArea(int area) {
+    general_timer_.SetArea(area);
+    if (software_timer_)
+      software_timer_->SetArea(area);
+    if (gpu_timer_)
+      gpu_timer_->SetArea(area);
+  }
+
+ private:
+  ScopedGeneralRasterTaskTimer general_timer_;
+  base::Optional<ScopedSoftwareRasterTaskTimer> software_timer_;
+  base::Optional<ScopedGpuRasterTaskTimer> gpu_timer_;
+};
+
 class RasterTaskImpl : public TileTask {
  public:
   RasterTaskImpl(TileManager* tile_manager,
@@ -54,8 +90,8 @@ class RasterTaskImpl : public TileTask {
                  uint64_t source_prepare_tiles_id,
                  std::unique_ptr<RasterBuffer> raster_buffer,
                  TileTask::Vector* dependencies,
-                 bool supports_concurrent_execution)
-      : TileTask(supports_concurrent_execution, dependencies),
+                 bool is_gpu_rasterization)
+      : TileTask(!is_gpu_rasterization, dependencies),
         tile_manager_(tile_manager),
         tile_(tile),
         resource_(resource),
@@ -70,6 +106,7 @@ class RasterTaskImpl : public TileTask {
         tile_tracing_id_(static_cast<void*>(tile)),
         new_content_id_(tile->id()),
         source_frame_number_(tile->source_frame_number()),
+        is_gpu_rasterization_(is_gpu_rasterization),
         raster_buffer_(std::move(raster_buffer)) {
     DCHECK(origin_thread_checker_.CalledOnValidThread());
   }
@@ -84,7 +121,7 @@ class RasterTaskImpl : public TileTask {
 
     frame_viewer_instrumentation::ScopedRasterTask raster_task(
         tile_tracing_id_, tile_resolution_, source_frame_number_, layer_id_);
-    ScopedRasterTaskTimer timer;
+    ScopedRasterTaskTimer timer(is_gpu_rasterization_);
     timer.SetArea(content_rect_.size().GetArea());
 
     DCHECK(raster_source_);
@@ -133,6 +170,7 @@ class RasterTaskImpl : public TileTask {
   void* tile_tracing_id_;
   uint64_t new_content_id_;
   int source_frame_number_;
+  bool is_gpu_rasterization_;
   std::unique_ptr<RasterBuffer> raster_buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(RasterTaskImpl);
@@ -973,7 +1011,6 @@ scoped_refptr<TileTask> TileManager::CreateRasterTask(
       prepare_tiles_count_, prioritized_tile.priority().priority_bin);
   image_manager_.GetTasksForImagesAndRef(&images, &decode_tasks, tracing_info);
 
-  bool supports_concurrent_execution = !use_gpu_rasterization_;
   std::unique_ptr<RasterBuffer> raster_buffer =
       raster_buffer_provider_->AcquireBufferForRaster(
           resource, resource_content_id, tile->invalidated_id());
@@ -981,7 +1018,7 @@ scoped_refptr<TileTask> TileManager::CreateRasterTask(
       this, tile, resource, prioritized_tile.raster_source(), playback_settings,
       prioritized_tile.priority().resolution, invalidated_rect,
       prepare_tiles_count_, std::move(raster_buffer), &decode_tasks,
-      supports_concurrent_execution));
+      use_gpu_rasterization_));
 }
 
 void TileManager::OnRasterTaskCompleted(