diff -r 000000000000 -r 6474c204b198 browser/base/content/test/general/browser_backButtonFitts.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/base/content/test/general/browser_backButtonFitts.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+function test () {
+  waitForExplicitFinish();
+  var firstLocation = "http://example.org/browser/browser/base/content/test/general/dummy_page.html";
+  gBrowser.selectedTab = gBrowser.addTab(firstLocation);
+  gBrowser.selectedBrowser.addEventListener("pageshow", function onPageShow1() {
+    gBrowser.selectedBrowser.removeEventListener("pageshow", onPageShow1);
+    gBrowser.selectedBrowser.contentWindow.history.pushState("page2", "page2", "page2");
+    window.maximize();
+
+    // Find where the nav-bar is vertically.
+    var navBar = document.getElementById("nav-bar");
+    var boundingRect = navBar.getBoundingClientRect();
+    var yPixel = boundingRect.top + Math.floor(boundingRect.height / 2);
+    var xPixel = 0; // Use the first pixel of the screen since it is maximized.
+
+    gBrowser.selectedBrowser.contentWindow.addEventListener("popstate", function onPopState() {
+      gBrowser.selectedBrowser.contentWindow.removeEventListener("popstate", onPopState);
+      is(gBrowser.selectedBrowser.contentDocument.location.href, firstLocation,
+         "Clicking the first pixel should have navigated back.");
+      window.restore();
+      gBrowser.removeCurrentTab();
+      finish();
+    });
+    EventUtils.synthesizeMouseAtPoint(xPixel, yPixel, {}, window);
+  });
+}