Add observers to FrameSinkManagerHost.

content/browser/compositor/frame_sink_manager_host.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 CONTENT_BROWSER_COMPOSITOR_FRAME_SINK_MANAGER_HOST_H_
 #define CONTENT_BROWSER_COMPOSITOR_FRAME_SINK_MANAGER_HOST_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "cc/ipc/frame_sink_manager.mojom.h"
 #include "cc/surfaces/frame_sink_id.h"
 #include "components/viz/frame_sinks/mojo_frame_sink_manager.h"
+#include "content/browser/compositor/frame_sink_observer.h"
 #include "content/common/content_export.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 namespace cc {
 class SurfaceInfo;
 class SurfaceManager;
 }
 
 namespace content {
 
 // Browser side implementation of mojom::FrameSinkManager. Manages frame sinks
 // and is intended to replace SurfaceManager.
 class CONTENT_EXPORT FrameSinkManagerHost
     : NON_EXPORTED_BASE(cc::mojom::FrameSinkManagerClient) {
  public:
   FrameSinkManagerHost();
   ~FrameSinkManagerHost() override;
 
   cc::SurfaceManager* surface_manager();
 
   // Start Mojo connection to FrameSinkManager. Most tests won't need this.
   void ConnectToFrameSinkManager();
 
+  void AddObserver(FrameSinkObserver* observer);
+  void RemoveObserver(FrameSinkObserver* observer);
+
   // See frame_sink_manager.mojom for descriptions.
   void CreateCompositorFrameSink(
       const cc::FrameSinkId& frame_sink_id,
       cc::mojom::MojoCompositorFrameSinkRequest request,
       cc::mojom::MojoCompositorFrameSinkPrivateRequest private_request,
       cc::mojom::MojoCompositorFrameSinkClientPtr client);
   void RegisterFrameSinkHierarchy(const cc::FrameSinkId& parent_frame_sink_id,
                                   const cc::FrameSinkId& child_frame_sink_id);
   void UnregisterFrameSinkHierarchy(const cc::FrameSinkId& parent_frame_sink_id,
                                     const cc::FrameSinkId& child_frame_sink_id);
 
  private:
   // cc::mojom::FrameSinkManagerClient:
   void OnSurfaceCreated(const cc::SurfaceInfo& surface_info) override;
 
   // Mojo connection to |frame_sink_manager_|.
   cc::mojom::FrameSinkManagerPtr frame_sink_manager_ptr_;
 
   // Mojo connection back from |frame_sink_manager_|.
   mojo::Binding<cc::mojom::FrameSinkManagerClient> binding_;
 
   // This is owned here so that SurfaceManager will be accessible in process.
   // Other than using SurfaceManager, access to |frame_sink_manager_| should
   // happen using Mojo. See http://crbug.com/657959.
   viz::MojoFrameSinkManager frame_sink_manager_;
 
+  // Local observers to that receive OnSurfaceCreated() messages from IPC.
+  base::ObserverList<FrameSinkObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(FrameSinkManagerHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_FRAME_SINK_MANAGER_HOST_H_