Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media tracks

third_party/WebKit/Source/core/html/track/TrackListBase.h

Index: third_party/WebKit/Source/core/html/track/TrackListBase.h
diff --git a/third_party/WebKit/Source/core/html/track/TrackListBase.h b/third_party/WebKit/Source/core/html/track/TrackListBase.h
index d849da628d3e826233647210bf99bb8e375ef4e3..b5f70799b7a5719016f5f9d4742f088a68ba798f 100644
--- a/third_party/WebKit/Source/core/html/track/TrackListBase.h
+++ b/third_party/WebKit/Source/core/html/track/TrackListBase.h
@@ -100,6 +100,14 @@ public:
         EventTargetWithInlineData::trace(visitor);
     }
 
+    DECLARE_VIRTUAL_TRACE_WRAPPERS()
+    {
+        for (auto track : m_tracks) {
+            visitor->traceWrappers(track);
+        }
+        EventTargetWithInlineData::traceWrappers(visitor);
+    }
+
 private:
     void scheduleTrackEvent(const AtomicString& eventName, T* track)
     {