Bug 1208316 - Punch a hole for media element captureStream to only go inactive as source ends. r=jib

MozReview-Commit-ID: 3H0m3fYMw1Y

dom/html/HTMLMediaElement.cpp

@@ -2526,6 +2526,7 @@ HTMLMediaElement::CaptureStreamInternal(bool aFinishWhenEnded,
   OutputMediaStream* out = mOutputStreams.AppendElement();
   MediaStreamTrackSourceGetter* getter = new CaptureStreamTrackSourceGetter(this);
   out->mStream = DOMMediaStream::CreateTrackUnionStreamAsInput(window, aGraph, getter);
+  out->mStream->SetInactiveOnFinish();
   out->mFinishWhenEnded = aFinishWhenEnded;
   out->mCapturingAudioOnly = aCaptureAudio;