diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug624931.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug624931.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,91 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that there is a transform being applied to the tabs as they zoom in
+// and out.
+
+let tab, frontChanged, transformChanged;
+
+function test() {
+  waitForExplicitFinish();
+
+  window.addEventListener("tabviewshown", onTabViewWindowLoaded, false);
+  TabView.toggle();
+}
+
+function onTabViewWindowLoaded() {
+  window.removeEventListener("tabviewshown", onTabViewWindowLoaded, false);
+
+  let contentWindow = document.getElementById("tab-view").contentWindow;
+  tab = contentWindow.UI.getActiveTab();
+  ok(tab, "We have an active tab");
+
+  frontChanged = transformChanged = false;
+  tab.$container[0].addEventListener("DOMAttrModified", checkForFrontAddition,
+                                     false);
+  tab.$canvas[0].addEventListener("DOMAttrModified", checkForTransformAddition,
+                                  false);
+
+  window.addEventListener("tabviewhidden", onTabViewHidden, false);
+  TabView.toggle();
+}
+
+function checkForFrontAddition(aEvent) {
+  if (aEvent.attrName == "class" &&
+      aEvent.target.classList.contains("front")) {
+    frontChanged = true;
+  }
+}
+
+function checkForTransformAddition(aEvent) {
+  if (aEvent.attrName == "style" && aEvent.target.style.transform) {
+    transformChanged = true;
+  }
+}
+
+function onTabViewHidden() {
+  window.removeEventListener("tabviewhidden", onTabViewHidden, false);
+
+  ok(frontChanged, "the CSS class 'front' was added while zooming in");
+  ok(transformChanged, "the CSS class 'transform' was modified while " +
+     "zooming in");
+
+  frontChanged = transformChanged = false;
+  tab.$container[0].removeEventListener("DOMAttrModified",
+                                        checkForFrontAddition, false);
+  tab.$container[0].addEventListener("DOMAttrModified", checkForFrontRemoval,
+                                     false);
+
+  window.addEventListener("tabviewshown", onTabViewShownAgain, false);
+  TabView.toggle();
+}
+
+function checkForFrontRemoval(aEvent) {
+  if (aEvent.attrName == "class" &&
+      !aEvent.target.classList.contains("front")) {
+    frontChanged = true;
+  }
+}
+
+function onTabViewShownAgain() {
+  window.removeEventListener("tabviewshown", onTabViewShownAgain, false);
+
+  ok(frontChanged, "the CSS class 'front' was removed while zooming out");
+  ok(transformChanged, "the CSS class 'transform' was removed while zooming " +
+     "out");
+
+  tab.$container[0].removeEventListener("DOMAttrModified",
+                                        checkForFrontRemoval, false);
+  tab.$canvas[0].removeEventListener("DOMAttrModified",
+                                     checkForTransformAddition, false);
+
+  window.addEventListener("tabviewhidden", onTabViewHiddenAgain, false);
+  TabView.toggle();
+}
+
+function onTabViewHiddenAgain() {
+  window.removeEventListener("tabviewhidden", onTabViewHiddenAgain, false);
+
+  finish();
+}
+