Video Capture: Allow suspension of individual devices.

content/renderer/media/video_capture_impl_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.
 
 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_MANAGER_H_
 #define CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_MANAGER_H_
 
-#include <map>
 #include <memory>
+#include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
 #include "content/common/media/video_capture.h"
@@ skipping 50 matching lines @@
   base::Closure StartCapture(
       media::VideoCaptureSessionId id,
       const media::VideoCaptureParams& params,
       const VideoCaptureStateUpdateCB& state_update_cb,
       const VideoCaptureDeliverFrameCB& deliver_frame_cb);
 
   // Requests that the video capturer send a frame "soon" (e.g., to resolve
   // picture loss or quality issues).
   void RequestRefreshFrame(media::VideoCaptureSessionId id);
 
+  // Requests frame delivery be suspended/resumed for a given capture session.
+  void Suspend(media::VideoCaptureSessionId id);
+  void Resume(media::VideoCaptureSessionId id);
+
   // Get supported formats supported by the device for the given session
   // ID. |callback| will be called on the IO thread.
   void GetDeviceSupportedFormats(media::VideoCaptureSessionId id,
                                  const VideoCaptureDeviceFormatsCB& callback);
 
   // Get supported formats currently in use for the given session ID.
   // |callback| will be called on the IO thread.
   void GetDeviceFormatsInUse(media::VideoCaptureSessionId id,
                              const VideoCaptureDeviceFormatsCB& callback);
 
   // Make all existing VideoCaptureImpl instances stop/resume delivering
-  // video frames to their clients, depends on flag |suspend|.
+  // video frames to their clients, depends on flag |suspend|. This is called in
+  // response to a RenderView-wide PageHidden/Shown() event. To suspend/resume
+  // an individual session, please call Suspend(id) or Resume(id).
   void SuspendDevices(bool suspend);
 
   VideoCaptureMessageFilter* video_capture_message_filter() const {
     return filter_.get();
   }
 
  protected:
-  virtual VideoCaptureImpl* CreateVideoCaptureImplForTesting(
+  virtual std::unique_ptr<VideoCaptureImpl> CreateVideoCaptureImplForTesting(
       media::VideoCaptureSessionId id,
       VideoCaptureMessageFilter* filter) const;
 
  private:
+  // Holds bookkeeping info for each VideoCaptureImpl shared by clients.
+  struct DeviceEntry;
+
   void StopCapture(int client_id, media::VideoCaptureSessionId id);
   void UnrefDevice(media::VideoCaptureSessionId id);
 
-  // The int is used to count clients of the corresponding VideoCaptureImpl.
-  // VideoCaptureImpl objects are owned by this object. But they are
-  // destroyed on the IO thread. These are raw pointers because we destroy
-  // them manually.
-  typedef std::map<media::VideoCaptureSessionId,
-                   std::pair<int, VideoCaptureImpl*>> VideoCaptureDeviceMap;
-  VideoCaptureDeviceMap devices_;
+  // Devices currently in use.
+  std::vector<DeviceEntry> devices_;
 
   // This is an internal ID for identifying clients of VideoCaptureImpl.
   // The ID is global for the render process.
   int next_client_id_;
 
   const scoped_refptr<VideoCaptureMessageFilter> filter_;
 
   // Hold a pointer to the Render Main message loop to check we operate on the
   // right thread.
   const scoped_refptr<base::SingleThreadTaskRunner> render_main_task_runner_;
 
+  // Set to true if SuspendDevices(true) was called. This, along with
+  // DeviceEntry::is_individually_suspended, is used to determine whether to
+  // take action when suspending/resuming each device.
+  bool is_suspending_all_;
+
   // Bound to the render thread.
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<VideoCaptureImplManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureImplManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_MANAGER_H_