--- a/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java
@@ -2842,17 +2842,17 @@ public class GeckoSession extends LayerS
                     throw new IllegalArgumentException("String: " + type + " is not a valid media type string");
                 }
             }
 
             /* package */ MediaSource(GeckoBundle media) {
                 id = media.getString("id");
                 rawId = media.getString("rawId");
                 name = media.getString("name");
-                source = getSourceFromString(media.getString("source"));
+                source = getSourceFromString(media.getString("mediaSource"));
                 type = getTypeFromString(media.getString("type"));
             }
         }
 
         /**
          * Callback interface for notifying the result of a media permission request,
          * including which media source(s) to use.
          */