Replace usage of WebVector::isEmpty with WebVector::empty().

content/renderer/media/video_track_to_pepper_adapter.cc

Index: content/renderer/media/video_track_to_pepper_adapter.cc
diff --git a/content/renderer/media/video_track_to_pepper_adapter.cc b/content/renderer/media/video_track_to_pepper_adapter.cc
index f7fef9179169ec4ce72597999c4366204cbee2ab..316e133cfcc95e7a7cde196f238e07a54eb09446 100644
--- a/content/renderer/media/video_track_to_pepper_adapter.cc
+++ b/content/renderer/media/video_track_to_pepper_adapter.cc
@@ -111,7 +111,7 @@ blink::WebMediaStreamTrack VideoTrackToPepperAdapter::GetFirstVideoTrack(
   // Get the first video track from the stream.
   blink::WebVector<blink::WebMediaStreamTrack> video_tracks;
   stream.videoTracks(video_tracks);
-  if (video_tracks.isEmpty()) {
+  if (video_tracks.empty()) {
     LOG(ERROR) << "GetFirstVideoSource - no video tracks. url: " << url;
     return blink::WebMediaStreamTrack();
   }