b=1023697 use MediaStream to convert stream time to seconds in HTMLMediaElement r=roc

--HG--
extra : transplant_source : %7D%AF%00%8F%0F4%E3%3C.%F7%E2%92%BA%CB%92%0E/%19%CFM

content/html/content/src/HTMLMediaElement.cpp

@@ -1280,7 +1280,7 @@ HTMLMediaElement::CurrentTime() const
   if (mSrcStream) {
     MediaStream* stream = GetSrcMediaStream();
     if (stream) {
-      return MediaTimeToSeconds(stream->GetCurrentTime());
+      return stream->StreamTimeToSeconds(stream->GetCurrentTime());
     }
   }