diff -r 000000000000 -r 6474c204b198 browser/experiments/ExperimentsService.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/experiments/ExperimentsService.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,110 @@
+/* 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/. */
+
+"use strict";
+
+const {interfaces: Ci, utils: Cu} = Components;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Preferences.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Experiments",
+                                  "resource:///modules/experiments/Experiments.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "OS",
+                                  "resource://gre/modules/osfile.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "CommonUtils",
+                                  "resource://services-common/utils.js");
+
+const PREF_EXPERIMENTS_ENABLED  = "experiments.enabled";
+const PREF_ACTIVE_EXPERIMENT    = "experiments.activeExperiment"; // whether we have an active experiment
+const PREF_HEALTHREPORT_ENABLED = "datareporting.healthreport.service.enabled";
+const PREF_TELEMETRY_ENABLED    = "toolkit.telemetry.enabled";
+const DELAY_INIT_MS             = 30 * 1000;
+
+XPCOMUtils.defineLazyGetter(
+  this, "gPrefs", () => {
+    return new Preferences();
+  });
+
+XPCOMUtils.defineLazyGetter(
+  this, "gExperimentsEnabled", () => {
+    return gPrefs.get(PREF_EXPERIMENTS_ENABLED, false) &&
+           gPrefs.get(PREF_TELEMETRY_ENABLED, false) &&
+           gPrefs.get(PREF_HEALTHREPORT_ENABLED, false);
+  });
+
+XPCOMUtils.defineLazyGetter(
+  this, "gActiveExperiment", () => {
+    return gPrefs.get(PREF_ACTIVE_EXPERIMENT);
+  });
+
+function ExperimentsService() {
+  this._initialized = false;
+  this._delayedInitTimer = null;
+}
+
+ExperimentsService.prototype = {
+  classID: Components.ID("{f7800463-3b97-47f9-9341-b7617e6d8d49}"),
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsITimerCallback, Ci.nsIObserver]),
+
+  notify: function (timer) {
+    if (!gExperimentsEnabled) {
+      return;
+    }
+    if (OS.Constants.Path.profileDir === undefined) {
+      throw Error("Update timer fired before profile was initialized?");
+    }
+    Experiments.instance().updateManifest();
+  },
+
+  _delayedInit: function () {
+    if (!this._initialized) {
+      this._initialized = true;
+      Experiments.instance(); // for side effects
+    }
+  },
+
+  observe: function (subject, topic, data) {
+    switch (topic) {
+      case "profile-after-change":
+        if (gExperimentsEnabled) {
+          Services.obs.addObserver(this, "quit-application", false);
+          Services.obs.addObserver(this, "sessionstore-state-finalized", false);
+          Services.obs.addObserver(this, "EM-loaded", false);
+
+          if (gActiveExperiment) {
+            this._initialized = true;
+            Experiments.instance(); // for side effects
+          }
+        }
+        break;
+      case "sessionstore-state-finalized":
+        if (!this._initialized) {
+          CommonUtils.namedTimer(this._delayedInit, DELAY_INIT_MS, this, "_delayedInitTimer");
+        }
+        break;
+      case "EM-loaded":
+        if (!this._initialized) {
+          Experiments.instance(); // for side effects
+          this._initialized = true;
+
+          if (this._delayedInitTimer) {
+            this._delayedInitTimer.clear();
+          }
+        }
+        break;
+      case "quit-application":
+        Services.obs.removeObserver(this, "quit-application");
+        Services.obs.removeObserver(this, "sessionstore-state-finalized");
+        Services.obs.removeObserver(this, "EM-loaded");
+        if (this._delayedInitTimer) {
+          this._delayedInitTimer.clear();
+        }
+        break;
+    }
+  },
+};
+
+this.NSGetFactory = XPCOMUtils.generateNSGetFactory([ExperimentsService]);