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..1727bca4889f98d704916fd6884313334676d1d0 100644
--- a/services/ui/surfaces/display_output_surface.h
+++ b/services/ui/surfaces/display_output_surface.h
@@ -15,6 +15,7 @@ class SyntheticBeginFrameSource;
 }
 
 namespace ui {
+class LatencyTracker;
 
 // An OutputSurface implementation that directly draws and
 // swaps to an actual GL surface.
@@ -54,7 +55,7 @@ class DisplayOutputSurface : public cc::OutputSurface {
  private:
   // Called when a swap completion is signaled from ImageTransportSurface.
   void OnGpuSwapBuffersCompleted(
-      const std::vector<ui::LatencyInfo>& latency_info,
+      const std::vector<LatencyInfo>& latency_info,
       gfx::SwapResult result,
       const gpu::GpuProcessHostedCALayerTreeParamsMac* params_mac);
   void OnVSyncParametersUpdated(base::TimeTicks timebase,
@@ -62,6 +63,8 @@ class DisplayOutputSurface : public cc::OutputSurface {
 
   cc::OutputSurfaceClient* client_ = nullptr;
   cc::SyntheticBeginFrameSource* const synthetic_begin_frame_source_;
+  std::unique_ptr<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;