Allow muting/unmuting audio through media track API

third_party/WebKit/Source/web/WebRuntimeFeatures.cpp

Index: third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
diff --git a/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp b/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
index 5595abb3526746cd0a2b5b15ea38899cc0e16937..34707e483e15e96966f2686110cf704b877b82b2 100644
--- a/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
+++ b/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
@@ -320,4 +320,9 @@ bool WebRuntimeFeatures::isServiceWorkerExtendableMessageEventEnabled()
     return RuntimeEnabledFeatures::serviceWorkerExtendableMessageEventEnabled();
 }
 
+bool WebRuntimeFeatures::audioVideoTracksEnabled()
+{
+    return RuntimeEnabledFeatures::audioVideoTracksEnabled();
+}
+
 } // namespace blink