GpuDisplayCompositorFrameSink => GpuRootCompositorFrameSink

components/display_compositor/gpu_compositor_frame_sink_delegate.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_DISPLAY_COMPOSITOR_GPU_COMPOSITOR_FRAME_SINK_DELEGATE_H_
 #define COMPONENTS_DISPLAY_COMPOSITOR_GPU_COMPOSITOR_FRAME_SINK_DELEGATE_H_
 
+namespace cc {
+class FrameSinkId;
+}
+
 namespace display_compositor {
 
 class GpuCompositorFrameSinkDelegate {
  public:
   // We must avoid destroying a GpuCompositorFrameSink until both the display
   // compositor host and the client drop their connection to avoid getting into
   // a state where surfaces references are inconsistent.
   virtual void OnClientConnectionLost(const cc::FrameSinkId& frame_sink_id,
                                       bool destroy_compositor_frame_sink) = 0;
   virtual void OnPrivateConnectionLost(const cc::FrameSinkId& frame_sink_id,
                                        bool destroy_compositor_frame_sink) = 0;
 
  protected:
   virtual ~GpuCompositorFrameSinkDelegate() {}
 };
 
 }  // namespace display_compositor
 
 #endif  // COMPONENTS_DISPLAY_COMPOSITOR_GPU_COMPOSITOR_FRAME_SINK_DELEGATE_H_