enable video capture to support sharing across multiple renderer processes

content/browser/renderer_host/media/video_capture_manager.h

 // Copyright (c) 2011 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.
 
-// VideoCaptureManager is used to open/close, start/stop as well as enumerate
-// available video capture devices. All functions are expected to be called from
-// the Browser::IO thread. VideoCaptureManager will open OS dependent instances
-// of VideoCaptureDevice. A device can only be opened once.
+// VideoCaptureManager is used to open/close, start/stop, enumerate available
+// video capture devices, and manage VideoCaptureController's.
+// All functions are expected to be called from Browser::IO thread.
+// VideoCaptureManager will open OS dependent instances of VideoCaptureDevice.
+// A device can only be opened once.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 
+#include <list>
 #include <map>
 
 #include "base/threading/thread.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "media/video/capture/video_capture_device.h"
 #include "media/video/capture/video_capture_types.h"
 
+class VideoCaptureController;
+class VideoCaptureControllerEventHandler;
+
 namespace media_stream {
 
 // VideoCaptureManager opens/closes and start/stops video capture devices.
 class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
  public:
   // Calling |Start| of this id will open the first device, even though open has
   // not been called. This is used to be able to use video capture devices
   // before MediaStream is implemented in Chrome and WebKit.
   enum { kStartOpenSessionId = 1 };
 
@@ skipping 27 matching lines @@
   // A capture device error has occurred for |capture_session_id|. The device
   // won't stream any more captured frames.
   void Error(const media::VideoCaptureSessionId& capture_session_id);
 
   // Used by unit test to make sure a fake device is used instead of a real
   // video capture device. Due to timing requirements, the function must be
   // called before EnumerateDevices and Open.
   void UseFakeDevice();
   MessageLoop* GetMessageLoop();
 
+  // Called by VideoCaptureHost to get a controller for |capture_params|.
+  // The controller is returned via calling |added_cb|.
+  void AddController(
+      const media::VideoCaptureParams& capture_params,
+      VideoCaptureControllerEventHandler* handler,
+      base::Callback<void(VideoCaptureController*)> added_cb);
+  // Called by VideoCaptureHost to remove the |controller|.
+  void RemoveController(
+      VideoCaptureController* controller,
+      VideoCaptureControllerEventHandler* handler);
+
  private:
+  typedef std::list<VideoCaptureControllerEventHandler*> Handlers;
+  struct Controller;
+
   // Called by the public functions, executed on vc_device_thread_.
   void OnEnumerateDevices();
   void OnOpen(int capture_session_id, const StreamDeviceInfo& device);
   void OnClose(int capture_session_id);
   void OnStart(const media::VideoCaptureParams capture_params,
                media::VideoCaptureDevice::EventHandler* video_capture_receiver);
   void OnStop(const media::VideoCaptureSessionId capture_session_id,
               base::Closure stopped_cb);
+  void DoAddControllerOnDeviceThread(
+      const media::VideoCaptureParams capture_params,
+      VideoCaptureControllerEventHandler* handler,
+      base::Callback<void(VideoCaptureController*)> added_cb);
+  void DoRemoveControllerOnDeviceThread(
+      VideoCaptureController* controller,
+      VideoCaptureControllerEventHandler* handler);
 
   // Executed on Browser::IO thread to call Listener.
   void OnOpened(int capture_session_id);
   void OnClosed(int capture_session_id);
   void OnDevicesEnumerated(const StreamDeviceInfoArray& devices);
   void OnError(int capture_session_id, MediaStreamProviderError error);
 
   // Executed on vc_device_thread_ to make sure Listener is called from
   // Browser::IO thread.
   void PostOnOpened(int capture_session_id);
   void PostOnClosed(int capture_session_id);
   void PostOnDevicesEnumerated(const StreamDeviceInfoArray& devices);
   void PostOnError(int capture_session_id, MediaStreamProviderError error);
 
   // Helpers
   void GetAvailableDevices(media::VideoCaptureDevice::Names* device_names);
   bool DeviceOpened(const media::VideoCaptureDevice::Name& device_name);
   bool DeviceOpened(const StreamDeviceInfo& device_info);
   bool IsOnCaptureDeviceThread() const;
+  media::VideoCaptureDevice* GetDeviceInternal(int capture_session_id);
 
   // Thread for all calls to VideoCaptureDevice.
   base::Thread vc_device_thread_;
 
   // Only accessed on Browser::IO thread.
   MediaStreamProviderListener* listener_;
   int new_capture_session_id_;
 
   // Only accessed from vc_device_thread_.
   // VideoCaptureManager owns all VideoCaptureDevices and is responsible for
   // deleting the instances when they are not used any longer.
   typedef std::map<int, media::VideoCaptureDevice*> VideoCaptureDevices;
   VideoCaptureDevices devices_;
 
   // Set to true if using fake devices for testing, false by default.
   bool use_fake_device_;
 
+  // Only accessed from vc_device_thread_.
+  // VideoCaptureManager owns all VideoCaptureController's and is responsible
+  // for deleting the instances when they are not used any longer.
+  // VideoCaptureDevice is one-to-one mapped to VideoCaptureController.
+  typedef std::map<media::VideoCaptureDevice*, Controller*> Controllers;
+  Controllers controllers_;
+
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };
 
 }  // namespace media_stream
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(media_stream::VideoCaptureManager);
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_