Begin adding support for tab mirroring via the MediaStream audio/video capturing

content/browser/renderer_host/media/media_stream_manager.h

 // Copyright (c) 2012 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.
 
 // MediaStreamManager is used to open/enumerate media capture devices (video
 // supported now). Call flow:
 // 1. GenerateStream is called when a render process wants to use a capture
 //    device.
 // 2. MediaStreamManager will ask MediaStreamDeviceSettings for permission to
 //    use devices and for which device to use.
 // 3. MediaStreamManager will request the corresponding media device manager(s)
 //    to enumerate available devices. The result will be given to
 //    MediaStreamDeviceSettings.
 // 4. MediaStreamDeviceSettings will, by using user settings, pick devices which
 //    devices to use and let MediaStreamManager know the result.
 // 5. MediaStreamManager will call the proper media device manager to open the
 //    device and let the MediaStreamRequester know it has been done.
 
 // When enumeration and open are done in separate operations,
 // MediaStreamDeviceSettings is not involved as in steps.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_MANAGER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_MANAGER_H_
 
 #include <map>
 #include <string>
-#include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop.h"
 #include "base/system_monitor/system_monitor.h"
 #include "base/threading/thread.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/browser/renderer_host/media/media_stream_settings_requester.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace base {
 namespace win {
 class ScopedCOMInitializer;
 }
 }
 
+namespace media {
+class AudioManager;
+}
+
 namespace media_stream {
 
 class AudioInputDeviceManager;
 class MediaStreamDeviceSettings;
 class MediaStreamRequester;
 class VideoCaptureManager;
 
 // Thread that enters MTA on windows, and is base::Thread on linux and mac.
 class DeviceThread : public base::Thread {
  public:
@@ skipping 12 matching lines @@
 // MediaStreamManager is used to generate and close new media devices, not to
 // start the media flow.
 // The classes requesting new media streams are answered using
 // MediaStreamManager::Listener.
 class CONTENT_EXPORT MediaStreamManager
     : public MediaStreamProviderListener,
       public MessageLoop::DestructionObserver,
       public SettingsRequester,
       public base::SystemMonitor::DevicesChangedObserver {
  public:
-  // This class takes the ownerships of the |audio_input_device_manager|
-  // and |video_capture_manager|.
-  MediaStreamManager(AudioInputDeviceManager* audio_input_device_manager,
-                     VideoCaptureManager* video_capture_manager);
-
+  explicit MediaStreamManager(media::AudioManager* audio_manager);
   virtual ~MediaStreamManager();
 
   // Used to access VideoCaptureManager.
   VideoCaptureManager* video_capture_manager();
 
   // Used to access AudioInputDeviceManager.
   AudioInputDeviceManager* audio_input_device_manager();
 
-  // GenerateStream opens new media devices according to |components|. It
+  // GenerateStream opens new media devices according to |components|.  It
   // creates a new request which is identified by a unique |label| that's
-  // returned to the caller.
+  // returned to the caller.  |render_process_id| and |render_view_id| refer to
+  // the view where the infobar will appear to the user.
   void GenerateStream(MediaStreamRequester* requester, int render_process_id,
-                      int render_view_id, const StreamOptions& options,
+                      int render_view_id, const StreamOptions& components,
                       const GURL& security_origin, std::string* label);
 
+  // Like GenerateStream above, except the user is only able to allow/deny the
+  // request for the device specified by |device_id|.
+  void GenerateStreamForDevice(MediaStreamRequester* requester,
+                               int render_process_id, int render_view_id,
+                               const StreamOptions& components,
+                               const std::string& device_id,
+                               const GURL& security_origin, std::string* label);
+
   // Cancel generate stream.
   void CancelGenerateStream(const std::string& label);
 
   // Closes generated stream.
   void StopGeneratedStream(const std::string& label);
 
-  // Gets a list of devices of |type|.
+  // Gets a list of devices of |type|, which must be MEDIA_DEVICE_AUDIO_CAPTURE
+  // or MEDIA_DEVICE_VIDEO_CAPTURE.
   // The request is identified using |label|, which is pointing to a
   // std::string.
   // The request is persistent, which means the client keeps listening to
   // device changes, such as plug/unplug, and expects new device list for
   // such a change, till the client stops the request.
   void EnumerateDevices(MediaStreamRequester* requester,
                         int render_process_id,
                         int render_view_id,
                         MediaStreamType type,
                         const GURL& security_origin,
                         std::string* label);
 
-  // Open a device identified by |device_id|.
+  // Open a device identified by |device_id|.  |type| must be either
+  // MEDIA_DEVICE_AUDIO_CAPTURE or MEDIA_DEVICE_VIDEO_CAPTURE.
   // The request is identified using |label|, which is pointing to a
   // std::string.
   void OpenDevice(MediaStreamRequester* requester,
                   int render_process_id,
                   int render_view_id,
                   const std::string& device_id,
                   MediaStreamType type,
                   const GURL& security_origin,
                   std::string* label);
 
@@ skipping 46 matching lines @@
   void NotifyObserverDevicesOpened(DeviceRequest* request);
   void NotifyObserverDevicesClosed(DeviceRequest* request);
   void DevicesFromRequest(DeviceRequest* request,
                           content::MediaStreamDevices* devices);
 
   // Helpers.
   bool RequestDone(const MediaStreamManager::DeviceRequest& request) const;
   MediaStreamProvider* GetDeviceManager(MediaStreamType stream_type);
   void StartEnumeration(DeviceRequest* new_request,
                         std::string* label);
-  void AddRequest(DeviceRequest* new_request, std::string* label);
+  void AddRequest(const DeviceRequest& new_request, std::string* label);
   bool HasEnumerationRequest(MediaStreamType type);
   bool HasEnumerationRequest();
   void ClearEnumerationCache(EnumerationCache* cache);
 
-  // Helper to ensure the device thread and pass the message loop to device
-  // managers, it also register itself as the listener to the device managers.
-  void EnsureDeviceThreadAndListener();
+  // Helper to create the device managers, if needed.  Auto-starts the device
+  // thread and registers this as a listener with the device managers.
+  void EnsureDeviceManagersStarted();
 
   // Sends cached device list to a client corresponding to the request
   // identified by |label|.
   void SendCachedDeviceList(EnumerationCache* cache, const std::string& label);
 
   // Stop the request of enumerating devices indentified by |label|.
   void StopEnumerateDevices(const std::string& label);
 
   // Helpers to start and stop monitoring devices.
   void StartMonitoring();
   void StopMonitoring();
 
   // Device thread shared by VideoCaptureManager and AudioInputDeviceManager.
   scoped_ptr<base::Thread> device_thread_;
 
   scoped_ptr<MediaStreamDeviceSettings> device_settings_;
+
+  media::AudioManager* const audio_manager_;  // not owned

[tommi (sloooow) - chröme, 2012/09/10 09:17:25]

chrome convention is: const media::AudioManager*
... on second thought, why is this const?

[miu, 2012/09/10 21:24:38]

The object isn't const.  The pointer is.  It is set once (in the constructor),
and the compiler guarantees audio_manager_ is not re-assigned some other pointer
afterwards.

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Use_of_const

   scoped_refptr<AudioInputDeviceManager> audio_input_device_manager_;
   scoped_refptr<VideoCaptureManager> video_capture_manager_;
 
   // Indicator of device monitoring state.
   bool monitoring_started_;
 
   // Stores most recently enumerated device lists. The cache is cleared when
   // monitoring is stopped or there is no request for that type of device.
   EnumerationCache audio_enumeration_cache_;
   EnumerationCache video_enumeration_cache_;
 
   // Keeps track of live enumeration commands sent to VideoCaptureManager or
   // AudioInputDeviceManager, in order to only enumerate when necessary.
-  int active_enumeration_ref_count_[content::NUM_MEDIA_STREAM_DEVICE_TYPES];
+  int active_enumeration_ref_count_[content::NUM_MEDIA_TYPES];
 
   // All non-closed request.
   typedef std::map<std::string, DeviceRequest> DeviceRequests;
   DeviceRequests requests_;
 
   // Hold a pointer to the IO loop to check we delete the device thread and
   // managers on the right thread.
   MessageLoop* io_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamManager);
 };
 
 }  // namespace media_stream
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_MANAGER_H_