WIP: Plumbing input event latency reporting through Mus GPU.

services/ui/surfaces/display_output_surface.h

Index: services/ui/surfaces/display_output_surface.h
diff --git a/services/ui/surfaces/display_output_surface.h b/services/ui/surfaces/display_output_surface.h
index 0861c1d7bbe1a3baaa2bd52965f7df687b4a500e..8801d47c254f5cb6a71468fdd38c09fcb0b3f827 100644
--- a/services/ui/surfaces/display_output_surface.h
+++ b/services/ui/surfaces/display_output_surface.h
@@ -14,6 +14,10 @@ namespace cc {
 class SyntheticBeginFrameSource;
 }
 
+namespace latency_tracker {
+class LatencyTracker;
+}
+
 namespace ui {
 
 // An OutputSurface implementation that directly draws and
@@ -61,7 +65,10 @@ class DisplayOutputSurface : public cc::OutputSurface {
                                 base::TimeDelta interval);
 
   cc::OutputSurfaceClient* client_ = nullptr;
+  gpu::InProcessCommandBuffer* in_process_command_buffer_ = nullptr;

[mfomitchev, 2017/03/23 15:09:10]

Is this okay?

   cc::SyntheticBeginFrameSource* const synthetic_begin_frame_source_;
+  std::unique_ptr<latency_tracker::LatencyTracker> latency_tracker_;
+
   bool set_draw_rectangle_for_frame_ = false;
   // True if the draw rectangle has been set at all since the last resize.
   bool has_set_draw_rectangle_since_last_resize_ = false;