diff --git a/content/media/TextTrackCue.cpp b/content/media/TextTrackCue.cpp
index ca06c4d6050..d80920b8483 100644
--- a/content/media/TextTrackCue.cpp
+++ b/content/media/TextTrackCue.cpp
@@ -41,7 +41,6 @@ TextTrackCue::SetDefaultCueSettings()
   mSnapToLines = true;
   mLine = WEBVTT_AUTO;
   mAlign = AlignSetting::Middle;
-  mLineAlign = AlignSetting::Start;
   mVertical = DirectionSetting::_empty;
 }
 
diff --git a/content/media/TextTrackCue.h b/content/media/TextTrackCue.h
index 545f1c5c820..70f34549131 100644
--- a/content/media/TextTrackCue.h
+++ b/content/media/TextTrackCue.h
@@ -174,26 +174,6 @@ public:
     mLine = aLine;
   }
 
-  AlignSetting LineAlign() const
-  {
-    return mLineAlign;
-  }
-
-  void SetLineAlign(AlignSetting& aLineAlign, ErrorResult& aRv)
-  {
-    if (mLineAlign == aLineAlign)
-      return;
-
-    if (aLineAlign == AlignSetting::Left ||
-        aLineAlign == AlignSetting::Right) {
-      return aRv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
-    }
-
-    mReset = true;
-    mLineAlign = aLineAlign;
-    CueChanged();
-  }
-
   int32_t Position() const
   {
     return mPosition;
@@ -344,7 +324,6 @@ private:
   DirectionSetting mVertical;
   int mLine;
   AlignSetting mAlign;
-  AlignSetting mLineAlign;
 
   // Holds the computed DOM elements that represent the parsed cue text.
   // http://www.whatwg.org/specs/web-apps/current-work/#text-track-cue-display-state
diff --git a/content/media/test/test_texttrackcue.html b/content/media/test/test_texttrackcue.html
index 81a259f6d93..f19cc76a1f7 100644
--- a/content/media/test/test_texttrackcue.html
+++ b/content/media/test/test_texttrackcue.html
@@ -72,34 +72,6 @@ SpecialPowers.pushPrefEnv({"set": [["media.webvtt.enabled", true]]},
       cue.pauseOnExit = true;
       is(cue.pauseOnExit, true, "Cue's pause on exit flag should be true.");
 
-      // Check that cue line align works properly
-      is(cue.lineAlign, "start", "Cue's default line alignment should be start.");
-
-      var exceptionHappened = false;
-      try {
-        cue.lineAlign = "left";
-      } catch(e) {
-        exceptionHappened = true;
-        is(e.name, "SyntaxError", "Should have thrown SyntaxError.");
-      }
-      ok(exceptionHappened, "Exception should have happened.");
-
-      exceptionHappened = false;
-      try {
-        cue.lineAlign = "right";
-      } catch(e) {
-        exceptionHappened = true;
-        is(e.name, "SyntaxError", "Should have thrown SyntaxError.");
-      }
-      ok(exceptionHappened, "Exception should have happened.");
-
-      cue.lineAlign = "middle";
-      is(cue.lineAlign, "middle", "Cue's line align should be middle.");
-      cue.lineAlign = "START";
-      is(cue.lineAlign, "middle", "Cue's line align should be middle.");
-      cue.lineAlign = "end";
-      is(cue.lineAlign, "end", "Cue's line align should be end.");
-
       // Check that we can create and add new VTTCues
       var vttCue = new VTTCue(3.999, 4, "foo");
       trackElement.track.addCue(vttCue);
@@ -119,7 +91,7 @@ SpecialPowers.pushPrefEnv({"set": [["media.webvtt.enabled", true]]},
       trackElement.track.removeCue(cue);
       is(cueList.length, 4, "Cue list length should be 4.");
 
-      exceptionHappened = false;
+      var exceptionHappened = false;
       try {
         // We should not be able to remove a cue that is not in the list.
         cue = new VTTCue(1, 2, "foo");
diff --git a/dom/webidl/VTTCue.webidl b/dom/webidl/VTTCue.webidl
index 5030ffaf204..7bab05095fb 100644
--- a/dom/webidl/VTTCue.webidl
+++ b/dom/webidl/VTTCue.webidl
@@ -38,8 +38,6 @@ interface VTTCue : EventTarget {
   // XXXhumph: https://www.w3.org/Bugs/Public/show_bug.cgi?id=20651
   // attribute (long or AutoKeyword) line;
   [SetterThrows]
-  attribute AlignSetting lineAlign;
-  [SetterThrows]
   attribute long position;
   [SetterThrows]
   attribute long size;