--- a/dom/html/test/file_fullscreen-utils.js
+++ b/dom/html/test/file_fullscreen-utils.js
@@ -1,23 +1,23 @@
 
 // Returns true if the window occupies the entire screen.
 // Note this only returns true once the transition from normal to
 // fullscreen mode is complete.
 function inFullscreenMode(win) {
-  return win.outerWidth == win.screen.width &&
-         win.outerHeight == win.screen.height;
+  return win.innerWidth == win.screen.width &&
+         win.innerHeight == win.screen.height;
 }
 
 // Returns true if the window is in normal mode, i.e. non fullscreen mode.
 // Note this only returns true once the transition from fullscreen back to
 // normal mode is complete.
 function inNormalMode(win) {
-  return win.outerWidth == win.normalSize.w &&
-         win.outerHeight == win.normalSize.h;
+  return win.innerWidth == win.normalSize.w &&
+         win.innerHeight == win.normalSize.h;
 }
 
 // Adds a listener that will be called once a fullscreen transition
 // is complete. When type==='enter', callback is called when we've
 // received a fullscreenchange event, and the fullscreen transition is
 // complete. When type==='exit', callback is called when we've
 // received a fullscreenchange event and the window dimensions match
 // the window dimensions when the window opened (so don't resize the
@@ -25,18 +25,18 @@ function inNormalMode(win) {
 // the listeners are added on, if absent, the listeners are added to
 // the current document.
 function addFullscreenChangeContinuation(type, callback, inDoc) {
   var doc = inDoc || document;
   var topWin = doc.defaultView.top;
   // Remember the window size in non-fullscreen mode.
   if (!topWin.normalSize) {
     topWin.normalSize = {
-      w: window.outerWidth,
-      h: window.outerHeight
+      w: window.innerWidth,
+      h: window.innerHeight
     };
   }
   function checkCondition() {
     if (type == "enter") {
       return inFullscreenMode(topWin);
     } else if (type == "exit") {
       // If we just revert the state to a previous fullscreen state,
       // the window won't back to the normal mode. Hence we check