WIP: Plumbing input event latency reporting through Mus GPU.

gpu/ipc/in_process_command_buffer.h

Index: gpu/ipc/in_process_command_buffer.h
diff --git a/gpu/ipc/in_process_command_buffer.h b/gpu/ipc/in_process_command_buffer.h
index ff29663a9254b1e39cedb58ab8a7d0e97745aae2..588599d439c026c475906a04c3ac5448509ea1aa 100644
--- a/gpu/ipc/in_process_command_buffer.h
+++ b/gpu/ipc/in_process_command_buffer.h
@@ -81,6 +81,9 @@ class GPU_EXPORT InProcessCommandBuffer : public CommandBuffer,
                                           public ImageTransportSurfaceDelegate {
  public:
   class Service;
+  typedef base::Callback<void(const std::vector<ui::LatencyInfo>&)>
+      LatencyInfoCallback;
+
   explicit InProcessCommandBuffer(const scoped_refptr<Service>& service);
   ~InProcessCommandBuffer() override;
 
@@ -131,6 +134,8 @@ class GPU_EXPORT InProcessCommandBuffer : public CommandBuffer,
                        const base::Closure& callback) override;
   void WaitSyncTokenHint(const SyncToken& sync_token) override;
   bool CanWaitUnverifiedSyncToken(const SyncToken& sync_token) override;
+  void AddLatencyInfo(
+      const std::vector<ui::LatencyInfo>& latency_info) override;
 
 // ImageTransportSurfaceDelegate implementation:
 #if defined(OS_WIN)
@@ -285,6 +290,9 @@ class GPU_EXPORT InProcessCommandBuffer : public CommandBuffer,
   bool delayed_work_pending_;
   ImageFactory* image_factory_;
 
+  LatencyInfoCallback latency_info_callback_;
+  std::vector<ui::LatencyInfo> latency_info_;
+
   // Members accessed on the client thread:
   GpuControlClient* gpu_control_client_;
 #if DCHECK_IS_ON()