Decouple GpuCompositorFrameSink from DisplayCompositor

cc/surfaces/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 CC_SURFACES_COMPOSITOR_FRAME_SINK_DELEGATE_H_
+#define CC_SURFACES_COMPOSITOR_FRAME_SINK_DELEGATE_H_
+
+#include "cc/surfaces/frame_sink_id.h"
+
+namespace cc {
+
+class CompositorFrameSinkDelegate {

[Fady Samuel, 2017/01/24 13:09:43]

Call it GpuCompositorFrameSinkDelegate. Also, it was discussed in another bug.
We'd like to place all service-side code in components/display_compositor.

Please place GpuCompositorFrameSinkDelegate, and GpuCompositorFrameSink,
GpuOffscreenCompositorFrameSink and GpuDisplayCompositorFrameSink in
components/display_compositor.

+ 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 FrameSinkId& frame_sink_id,
+                                      bool destroy_compositor_frame_sink) = 0;
+
+  virtual void OnPrivateConnectionLost(const FrameSinkId& frame_sink_id,
+                                       bool destroy_compositor_frame_sink) = 0;
+
+ protected:
+  virtual ~CompositorFrameSinkDelegate() {}
+};
+
+}  // namespace cc
+
+#endif  // CC_SURFACES_COMPOSITOR_FRAME_SINK_DELEGATE_H_