diff -r 000000000000 -r 6474c204b198 testing/mochitest/tests/SimpleTest/MemoryStats.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing/mochitest/tests/SimpleTest/MemoryStats.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,104 @@
+/* -*- js-indent-level: 4; tab-width: 4; indent-tabs-mode: nil -*- */
+/* vim:set ts=4 sw=4 sts=4 et: */
+/* 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/. */
+
+var MemoryStats = {};
+
+/**
+ * Statistics that we want to retrieve and display after every test is
+ * done.  The keys of this table are intended to be identical to the
+ * relevant attributes of nsIMemoryReporterManager.  However, since
+ * nsIMemoryReporterManager doesn't necessarily support all these
+ * statistics in all build configurations, we also use this table to
+ * tell us whether statistics are supported or not.
+ */
+var MEM_STAT_UNKNOWN = 0;
+var MEM_STAT_UNSUPPORTED = 1;
+var MEM_STAT_SUPPORTED = 2;
+
+MemoryStats._hasMemoryStatistics = {}
+MemoryStats._hasMemoryStatistics.vsize = MEM_STAT_UNKNOWN;
+MemoryStats._hasMemoryStatistics.vsizeMaxContiguous = MEM_STAT_UNKNOWN;
+MemoryStats._hasMemoryStatistics.residentFast = MEM_STAT_UNKNOWN;
+MemoryStats._hasMemoryStatistics.heapAllocated = MEM_STAT_UNKNOWN;
+
+MemoryStats._getService = function (className, interfaceName) {
+    var service;
+    try {
+        service = Cc[className].getService(Ci[interfaceName]);
+    } catch (e) {
+        service = SpecialPowers.Cc[className]
+                               .getService(SpecialPowers.Ci[interfaceName]);
+    }
+    return service;
+}
+
+MemoryStats._nsIFile = function (pathname) {
+    var f;
+    var contractID = "@mozilla.org/file/local;1";
+    try {
+        f = Cc[contractID].createInstance(Ci.nsIFile);
+    } catch(e) {
+        f = SpecialPowers.Cc[contractID].createInstance(SpecialPowers.Ci.nsIFile);
+    }
+    f.initWithPath(pathname);
+    return f;
+}
+
+MemoryStats.constructPathname = function (directory, basename) {
+    var d = MemoryStats._nsIFile(directory);
+    d.append(basename);
+    return d.path;
+}
+
+MemoryStats.dump = function (dumpFn,
+                             testNumber,
+                             testURL,
+                             dumpOutputDirectory,
+                             dumpAboutMemory,
+                             dumpDMD) {
+    var mrm = MemoryStats._getService("@mozilla.org/memory-reporter-manager;1",
+                                      "nsIMemoryReporterManager");
+    for (var stat in MemoryStats._hasMemoryStatistics) {
+        var supported = MemoryStats._hasMemoryStatistics[stat];
+        var firstAccess = false;
+        if (supported == MEM_STAT_UNKNOWN) {
+            firstAccess = true;
+            try {
+                var value = mrm[stat];
+                supported = MEM_STAT_SUPPORTED;
+            } catch (e) {
+                supported = MEM_STAT_UNSUPPORTED;
+            }
+            MemoryStats._hasMemoryStatistics[stat] = supported;
+        }
+        if (supported == MEM_STAT_SUPPORTED) {
+            dumpFn("TEST-INFO | MEMORY STAT " + stat + " after test: " + mrm[stat]);
+        } else if (firstAccess) {
+            dumpFn("TEST-INFO | MEMORY STAT " + stat + " not supported in this build configuration.");
+        }
+    }
+
+    if (dumpAboutMemory) {
+        var basename = "about-memory-" + testNumber + ".json.gz";
+        var dumpfile = MemoryStats.constructPathname(dumpOutputDirectory,
+                                                     basename);
+        dumpFn("TEST-INFO | " + testURL + " | MEMDUMP-START " + dumpfile);
+        var md = MemoryStats._getService("@mozilla.org/memory-info-dumper;1",
+                                         "nsIMemoryInfoDumper");
+        md.dumpMemoryReportsToNamedFile(dumpfile, function () {
+            dumpFn("TEST-INFO | " + testURL + " | MEMDUMP-END");
+        }, null);
+
+    }
+
+    if (dumpDMD && typeof(DMDReportAndDump) != undefined) {
+        var basename = "dmd-" + testNumber + ".txt";
+        var dumpfile = MemoryStats.constructPathname(dumpOutputDirectory,
+                                                     basename);
+        dumpFn("TEST-INFO | " + testURL + " | DMD-DUMP " + dumpfile);
+        DMDReportAndDump(dumpfile);
+    }
+};