cc: Add OutputSurface state snapshots.

content/browser/compositor/browser_compositor_output_surface.h

Index: content/browser/compositor/browser_compositor_output_surface.h
diff --git a/content/browser/compositor/browser_compositor_output_surface.h b/content/browser/compositor/browser_compositor_output_surface.h
index 8c8f56cac0d11ffea21a8139a87c82c69e2c536f..38e68ce2920fa1162675526b078849c5d34b65b3 100644
--- a/content/browser/compositor/browser_compositor_output_surface.h
+++ b/content/browser/compositor/browser_compositor_output_surface.h
@@ -39,6 +39,11 @@ class CONTENT_EXPORT BrowserCompositorOutputSurface
   bool HasExternalStencilTest() const override;
   void ApplyExternalStencil() override;
 
+  void OnUpdateVSyncParametersFromGpu(
+      const UpdateVSyncParametersCallback& callback,
+      base::TimeTicks timebase,
+      base::TimeDelta interval);
+
   void SetReflector(ReflectorImpl* reflector);
 
   // Called when |reflector_| was updated.
@@ -66,8 +71,9 @@ class CONTENT_EXPORT BrowserCompositorOutputSurface
       const scoped_refptr<cc::VulkanContextProvider>& vulkan_context_provider,
       const UpdateVSyncParametersCallback& update_vsync_parameters_callback);
 
-  const UpdateVSyncParametersCallback update_vsync_parameters_callback_;
+  UpdateVSyncParametersCallback update_vsync_parameters_callback_;
   ReflectorImpl* reflector_;
+  base::TimeTicks last_vsync_timebase_;
 
  private:
   std::unique_ptr<display_compositor::CompositorOverlayCandidateValidator>