Refactor VideoCapturerDelegate to use WeakPtr instead of refcount.

content/renderer/media/user_media_client_impl.cc

Index: content/renderer/media/user_media_client_impl.cc
diff --git a/content/renderer/media/user_media_client_impl.cc b/content/renderer/media/user_media_client_impl.cc
index 16d439a59966ee51186e2218f52d7db263dd5cf0..8bf45f5528198922554e1787859a5fabbd2e96e9 100644
--- a/content/renderer/media/user_media_client_impl.cc
+++ b/content/renderer/media/user_media_client_impl.cc
@@ -580,10 +580,11 @@ void UserMediaClientImpl::InitializeSourceObject(
 MediaStreamVideoSource* UserMediaClientImpl::CreateVideoSource(
     const StreamDeviceInfo& device,
     const MediaStreamSource::SourceStoppedCallback& stop_callback) {
+  scoped_ptr<VideoCapturerDelegate> delegate(new VideoCapturerDelegate(device));
   return new content::MediaStreamVideoCapturerSource(
       device,
       stop_callback,
-      new VideoCapturerDelegate(device));
+      delegate.Pass());
 }
 
 void UserMediaClientImpl::CreateVideoTracks(