diff -r 000000000000 -r 6474c204b198 layout/ipc/test-ipcbrowser-content.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/ipc/test-ipcbrowser-content.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,63 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function windowUtils() {
+    return content.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
+               .getInterface(Components.interfaces.nsIDOMWindowUtils);
+}
+
+function recvSetViewport(w, h) {
+
+    dump("setting viewport to "+ w +"x"+ h +"\n");
+
+    windowUtils().setCSSViewport(w, h);
+}
+
+function recvSetDisplayPort(x, y, w, h) {
+
+    dump("setting displayPort to <"+ x +", "+ y +", "+ w +", "+ h +">\n");
+
+    windowUtils().setDisplayPortForElement(x, y, w, h, content.document.documentElement, 0);
+}
+
+function recvSetResolution(xres, yres) {
+
+    dump("setting xres="+ xres +" yres="+ yres +"\n");
+
+    windowUtils().setResolution(xres, yres);
+}
+
+function recvScrollBy(dx, dy) {
+    content.scrollBy(dx, dy);
+}
+
+function recvScrollTo(x, y) {
+    content.scrollTo(x, y);
+}
+
+addMessageListener(
+    "setViewport",
+    function (m) { recvSetViewport(m.json.w, m.json.h); }
+);
+
+addMessageListener(
+    "setDisplayPort",
+    function (m) { recvSetDisplayPort(m.json.x, m.json.y,
+                                      m.json.w, m.json.h); }
+);
+
+addMessageListener(
+    "setResolution",
+    function (m) { recvSetResolution(m.json.xres, m.json.yres); }
+);
+
+addMessageListener(
+    "scrollBy",
+    function(m) { recvScrollBy(m.json.dx, m.json.dy); }
+);
+
+addMessageListener(
+    "scrollTo",
+    function(m) { recvScrollTo(m.json.x, m.json.y); }
+);