--- a/dom/webidl/HTMLMediaElement.webidl
+++ b/dom/webidl/HTMLMediaElement.webidl
@@ -207,12 +207,10 @@ partial interface HTMLMediaElement {
  *     "seeked" event.
  * (2) Otherwise, if the currentTime is larger or equal to the n-th frame's
  *     beginning time, then the SeekToNextFrame() operation sets the media's
  *     currentTime to the duration of the media source and dispatches a "seeked"
  *     event and an "ended" event.
  */
 partial interface HTMLMediaElement {
   [Throws, Pref="media.seekToNextFrame.enabled"]
-  void seekToNextFrame(); // This API should be an asynchronous one which
-                          // returns a Promise<void>. Bug 1276272 follows this
-                          // issue.
+  Promise<void> seekToNextFrame();
 };

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5447,10 +5447,10 @@ pref("dom.node.rootNode.enabled", true);
 // Default media volume
 pref("media.default_volume", "1.0");
 
 // Once bug 1276272 is resolved, we will trun this preference to default ON in
 // non-release channels.
 #ifdef RELEASE_BUILD
 pref("media.seekToNextFrame.enabled", false);
 #else
-pref("media.seekToNextFrame.enabled", false);
+pref("media.seekToNextFrame.enabled", true);
 #endif