--- a/b2g/chrome/content/shell.js
+++ b/b2g/chrome/content/shell.js
@@ -7,16 +7,17 @@
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 const Cr = Components.results;
 
 Cu.import('resource://gre/modules/XPCOMUtils.jsm');
 Cu.import('resource://gre/modules/Services.jsm');
 Cu.import('resource://gre/modules/ContactService.jsm');
+Cu.import('resource://gre/modules/SettingsChangeNotifier.jsm');
 Cu.import('resource://gre/modules/Webapps.jsm');
 
 XPCOMUtils.defineLazyServiceGetter(Services, 'env',
                                    '@mozilla.org/process/environment;1',
                                    'nsIEnvironment');
 
 XPCOMUtils.defineLazyServiceGetter(Services, 'ss',
                                    '@mozilla.org/content/style-sheet-service;1',

--- a/dom/settings/Makefile.in
+++ b/dom/settings/Makefile.in
@@ -20,16 +20,17 @@ EXTRA_COMPONENTS =         \
   SettingsManager.manifest \
   SettingsService.js \
   SettingsService.manifest \
   $(NULL)
 
 EXTRA_JS_MODULES =   \
   SettingsQueue.jsm  \
   SettingsDB.jsm     \
+  SettingsChangeNotifier.jsm \
   $(NULL)
 
 ifdef ENABLE_TESTS
 DIRS += tests
 endif
 
 # Add VPATH to LOCAL_INCLUDES so we are going to include the correct backend
 # subdirectory (and the ipc one).

new file mode 100644
--- /dev/null
+++ b/dom/settings/SettingsChangeNotifier.jsm
@@ -0,0 +1,56 @@
+/* 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"
+
+function debug(s) {
+//  dump("-*- SettingsChangeNotifier: " + s + "\n");
+}
+
+const Cu = Components.utils; 
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+let EXPORTED_SYMBOLS = ["SettingsChangeNotifier"];
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyGetter(this, "ppmm", function() {
+  return Cc["@mozilla.org/parentprocessmessagemanager;1"].getService(Ci.nsIFrameMessageManager);
+});
+
+
+let SettingsChangeNotifier = {
+  init: function() {
+    debug("init");
+    ppmm.addMessageListener("Settings:Changed", this);
+    Services.obs.addObserver(this, "xpcom-shutdown", false);
+  },
+
+  observe: function(aSubject, aTopic, aData) {
+    debug("observe");
+    ppmm.removeMessageListener("Settings:Changed", this);
+    Services.obs.removeObserver(this, "xpcom-shutdown");
+    ppmm = null;
+  },
+
+  receiveMessage: function(aMessage) {
+    debug("receiveMessage");
+    let msg = aMessage.json;
+    switch (aMessage.name) {
+      case "Settings:Changed":
+        ppmm.sendAsyncMessage("Settings:Change:Return:OK", { key: msg.key, value: msg.value });
+        Services.obs.notifyObservers(this, "mozsettings-changed", JSON.stringify({
+          key: msg.key,
+          value: msg.value
+        }));
+        break;
+      default: 
+        debug("Wrong message: " + aMessage.name);
+    }
+  }
+}
+
+SettingsChangeNotifier.init();

--- a/dom/settings/SettingsManager.js
+++ b/dom/settings/SettingsManager.js
@@ -1,30 +1,31 @@
 /* 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";
 
-/* static functions */
-let DEBUG = false;
-if (DEBUG)
-  debug = function (s) { dump("-*- SettingsManager: " + s + "\n"); };
-else
-  debug = function (s) {};
+function debug(s) {
+//  dump("-*- SettingsManager: " + s + "\n");
+}
 
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 Cu.import("resource://gre/modules/SettingsQueue.jsm");
 Cu.import("resource://gre/modules/SettingsDB.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 
+XPCOMUtils.defineLazyGetter(this, "cpmm", function() {
+  return Cc["@mozilla.org/childprocessmessagemanager;1"].getService(Ci.nsIFrameMessageManager);
+});
+
 const nsIClassInfo            = Ci.nsIClassInfo;
 const SETTINGSLOCK_CONTRACTID = "@mozilla.org/settingsLock;1";
 const SETTINGSLOCK_CID        = Components.ID("{ef95ddd0-6308-11e1-b86c-0800200c9a66}");
 const nsIDOMSettingsLock      = Ci.nsIDOMSettingsLock;
 
 function SettingsLock(aSettingsManager)
 {
   this._open = true;
@@ -62,20 +63,17 @@ SettingsLock.prototype = {
               //Workaround for cloning issues
               let obj = JSON.parse(JSON.stringify(info.settings[key]));
               req = store.put({settingName: key, settingValue: obj});
             }
 
             req.onsuccess = function() { 
               lock._open = true;
               Services.DOMRequest.fireSuccess(request, 0);
-              Services.obs.notifyObservers(lock, "mozsettings-changed", JSON.stringify({
-                key: key,
-                value: info.settings[key]
-              }));
+              cpmm.sendAsyncMessage("Settings:Changed", { key: key, value: info.settings[key] });
               lock._open = false;
             };
 
             req.onerror = function() { Services.DOMRequest.fireError(request, 0) };
           }
           break;
         case "get":
           if (info.name == "*") {
@@ -222,24 +220,47 @@ SettingsManager.prototype = {
     this._settingsDB.ensureDB(
       function() { lock.createTransactionAndProcess(); },
       function() { dump("ensureDB error cb!\n"); },
       myGlobal );
     this.nextTick(function() { this._open = false; }, lock);
     return lock;
   },
 
+  receiveMessage: function(aMessage) {
+    debug("Settings::receiveMessage: " + aMessage.name);
+    let msg = aMessage.json;
+
+    switch (aMessage.name) {
+      case "Settings:Change:Return:OK":
+        debug("Settings:Change:Return:OK");
+        if (!this._onsettingchange)
+          return;
+
+        debug('key:' + msg.key + ', value:' + msg.value + '\n');
+        let event = new this._window.MozSettingsEvent("settingchanged", {
+          settingName: msg.key,
+          settingValue: msg.value
+        });
+
+        this._onsettingchange.handleEvent(event);
+        break;
+      default: 
+        debug("Wrong message: " + aMessage.name);
+    }
+  },
+
   init: function(aWindow) {
     // Set navigator.mozSettings to null.
     if (!Services.prefs.getBoolPref("dom.mozSettings.enabled"))
       return null;
 
+    cpmm.addMessageListener("Settings:Change:Return:OK", this);
     this._window = aWindow;
     Services.obs.addObserver(this, "inner-window-destroyed", false);
-    Services.obs.addObserver(this, "mozsettings-changed", false);
     let util = aWindow.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
     this.innerWindowID = util.currentInnerWindowID;
 
     let principal = aWindow.document.nodePrincipal;
     let secMan = Cc["@mozilla.org/scriptsecuritymanager;1"].getService(Ci.nsIScriptSecurityManager);
     let readPerm = principal == secMan.getSystemPrincipal() ? Ci.nsIPermissionManager.ALLOW_ACTION : Services.perms.testExactPermission(principal.URI, "websettings-read");
     let readwritePerm = principal == secMan.getSystemPrincipal() ? Ci.nsIPermissionManager.ALLOW_ACTION : Services.perms.testExactPermission(principal.URI, "websettings-readwrite");
     this.hasReadPrivileges = readPerm == Ci.nsIPermissionManager.ALLOW_ACTION;
@@ -248,36 +269,24 @@ SettingsManager.prototype = {
   },
 
   observe: function(aSubject, aTopic, aData) {
     debug("Topic: " + aTopic);
     if (aTopic == "inner-window-destroyed") {
       let wId = aSubject.QueryInterface(Ci.nsISupportsPRUint64).data;
       if (wId == this.innerWindowID) {
         Services.obs.removeObserver(this, "inner-window-destroyed");
-        Services.obs.removeObserver(this, "mozsettings-changed");
+        cpmm.removeMessageListener("Settings:Change:Return:OK", this);
         this._requests = null;
         this._window = null;
         this._innerWindowID = null;
         this._onsettingchange = null;
         this._settingsDB.close();
+        cpmm = null;
       }
-    } else if (aTopic == "mozsettings-changed") {
-      if (!this._onsettingchange)
-        return;
-
-      let data = JSON.parse(aData);
-      debug('data:' + data.key + ':' + data.value + '\n');
-
-      let event = new this._window.MozSettingsEvent("settingchanged", {
-        settingName: data.key,
-        settingValue: data.value
-      });
-
-      this._onsettingchange.handleEvent(event);
     }
   },
 
   classID : SETTINGSMANAGER_CID,
   QueryInterface : XPCOMUtils.generateQI([nsIDOMSettingsManager, Ci.nsIDOMGlobalPropertyInitializer]),
 
   classInfo : XPCOMUtils.generateCI({classID: SETTINGSMANAGER_CID,
                                      contractID: SETTINGSMANAGER_CONTRACTID,