Release the camera when WebRTC is not visible in Android

content/browser/renderer_host/media/video_capture_controller.h

Index: content/browser/renderer_host/media/video_capture_controller.h
diff --git a/content/browser/renderer_host/media/video_capture_controller.h b/content/browser/renderer_host/media/video_capture_controller.h
index 2de5ff6bbf795cc898029dfd1afca9108015f281..9a4d61931157787eacef44f48d0487f59e16b8a9 100644
--- a/content/browser/renderer_host/media/video_capture_controller.h
+++ b/content/browser/renderer_host/media/video_capture_controller.h
@@ -96,7 +96,15 @@ class CONTENT_EXPORT VideoCaptureController {
   int RemoveClient(const VideoCaptureControllerID& id,
                    VideoCaptureControllerEventHandler* event_handler);
 
-  int GetClientCount();
+  // Pause or resume the video capture for specified client.
+  void PauseOrResumeClient(const VideoCaptureControllerID& id,
+                           VideoCaptureControllerEventHandler* event_handler,
+                           bool pause);
+
+  int GetClientCount() const;
+
+  // Return the number of clients that aren't paused.
+  int GetActiveClientCount() const;
 
   // API called directly by VideoCaptureManager in case the device is
   // prematurely closed.