From eb86cac0c7f6761cf48517170cd47db2f0f7f68f Mon Sep 17 00:00:00 2001
From: Sean Lin <selin@mozilla.com>
Date: Fri, 27 Jun 2014 15:58:47 +0800
Subject: [PATCH] Bug 1014023 - [Datastore] Notify apps of changes in datastore
 without being opened. r=baku, r=gene

---
 b2g/app/b2g.js                                |   4 +
 dom/datastore/DataStoreChangeNotifier.jsm     |  88 ++++++++++-
 dom/datastore/DataStoreService.cpp            |  45 ++++++
 dom/datastore/nsIDataStoreService.idl         |   5 +-
 .../tests/file_notify_system_message.html     | 122 ++++++++++++++++
 dom/datastore/tests/mochitest.ini             |   3 +
 dom/datastore/tests/test_app_install.html     |  10 +-
 dom/datastore/tests/test_arrays.html          |  10 +-
 dom/datastore/tests/test_basic.html           |  10 +-
 dom/datastore/tests/test_basic_worker.html    |  10 +-
 dom/datastore/tests/test_bug1008044.html      |  10 +-
 dom/datastore/tests/test_bug924104.html       |  10 +-
 dom/datastore/tests/test_bug957086.html       |  10 +-
 dom/datastore/tests/test_bug976311.html       |  10 +-
 dom/datastore/tests/test_bug986056.html       |  11 +-
 dom/datastore/tests/test_certifiedApp.html    |  10 +-
 dom/datastore/tests/test_changes.html         |  11 +-
 dom/datastore/tests/test_duplicate.html       |  10 +-
 dom/datastore/tests/test_keys.html            |  10 +-
 .../tests/test_notify_system_message.html     | 138 ++++++++++++++++++
 dom/datastore/tests/test_oop.html             |  10 +-
 dom/datastore/tests/test_oop_events.html      |  10 +-
 dom/datastore/tests/test_readonly.html        |  10 +-
 dom/datastore/tests/test_sync.html            |  10 +-
 dom/datastore/tests/test_sync_worker.html     |  10 +-
 dom/datastore/tests/test_transactions.html    |  10 +-
 dom/messages/SystemMessageInternal.js         |  61 +++++---
 .../SystemMessagePermissionsChecker.jsm       |  35 ++++-
 .../interfaces/nsISystemMessagesInternal.idl  |   6 +-
 29 files changed, 589 insertions(+), 110 deletions(-)
 create mode 100644 dom/datastore/tests/file_notify_system_message.html
 create mode 100644 dom/datastore/tests/test_notify_system_message.html

diff --git a/b2g/app/b2g.js b/b2g/app/b2g.js
index 9e46b6dcc3e..0080a4bf21d 100644
--- a/b2g/app/b2g.js
+++ b/b2g/app/b2g.js
@@ -886,6 +886,10 @@ pref("network.sntp.timeout", 30); // In seconds.
 
 // Enable dataStore
 pref("dom.datastore.enabled", true);
+// When an entry is changed, use two timers to fire system messages in a more
+// moderate pattern.
+pref("dom.datastore.sysMsgOnChangeShortTimeoutSec", 10);
+pref("dom.datastore.sysMsgOnChangeLongTimeoutSec", 60);
 
 // DOM Inter-App Communication API.
 pref("dom.inter-app-communication-api.enabled", true);
diff --git a/dom/datastore/DataStoreChangeNotifier.jsm b/dom/datastore/DataStoreChangeNotifier.jsm
index 64951f3ca43..bbf44a1f7ce 100644
--- a/dom/datastore/DataStoreChangeNotifier.jsm
+++ b/dom/datastore/DataStoreChangeNotifier.jsm
@@ -23,12 +23,33 @@ XPCOMUtils.defineLazyServiceGetter(this, "dataStoreService",
                                    "@mozilla.org/datastore-service;1",
                                    "nsIDataStoreService");
 
+XPCOMUtils.defineLazyServiceGetter(this, "systemMessenger",
+                                   "@mozilla.org/system-message-internal;1",
+                                   "nsISystemMessagesInternal");
+
+var kSysMsgOnChangeShortTimeoutSec =
+    Services.prefs.getIntPref("dom.datastore.sysMsgOnChangeShortTimeoutSec");
+var kSysMsgOnChangeLongTimeoutSec =
+    Services.prefs.getIntPref("dom.datastore.sysMsgOnChangeLongTimeoutSec");
+
 this.DataStoreChangeNotifier = {
   children: [],
   messages: [ "DataStore:Changed", "DataStore:RegisterForMessages",
               "DataStore:UnregisterForMessages",
               "child-process-shutdown" ],
 
+  // These hashes are used for storing the mapping between the datastore
+  // identifiers (name | owner manifest URL) and their correspondent timers. 
+  // The object literal is defined as below:
+  //
+  // {
+  //   "datastore name 1|owner manifest URL 1": timer1,
+  //   "datastore name 2|owner manifest URL 2": timer2,
+  //   ...
+  // }
+  sysMsgOnChangeShortTimers: {},
+  sysMsgOnChangeLongTimers: {},
+
   init: function() {
     debug("init");
 
@@ -59,7 +80,8 @@ this.DataStoreChangeNotifier = {
   },
 
   broadcastMessage: function broadcastMessage(aData) {
-    debug("Broadast");
+    debug("broadcast");
+
     this.children.forEach(function(obj) {
       if (obj.store == aData.store && obj.owner == aData.owner) {
         obj.mm.sendAsyncMessage("DataStore:Changed:Return:OK", aData);
@@ -67,6 +89,69 @@ this.DataStoreChangeNotifier = {
     });
   },
 
+  broadcastSystemMessage: function(aStore, aOwner) {
+    debug("broadcastSystemMessage");
+
+    // Clear relevant timers.
+    var storeKey = aStore + "|" + aOwner;
+    var shortTimer = this.sysMsgOnChangeShortTimers[storeKey];
+    if (shortTimer) {
+      shortTimer.cancel();
+      delete this.sysMsgOnChangeShortTimers[storeKey];
+    }
+    var longTimer = this.sysMsgOnChangeLongTimers[storeKey];
+    if (longTimer) {
+      longTimer.cancel();
+      delete this.sysMsgOnChangeLongTimers[storeKey];
+    }
+
+    // Get all the manifest URLs of the apps which can access the datastore.
+    var manifestURLs = dataStoreService.getAppManifestURLsForDataStore(aStore);
+    var enumerate = manifestURLs.enumerate();
+    while (enumerate.hasMoreElements()) {
+      var manifestURL = enumerate.getNext().QueryInterface(Ci.nsISupportsString);
+      debug("Notify app " + manifestURL + " of datastore updates");
+      // Send the system message 'datastore-update-{store name}' to all the
+      // pages for these apps. With the manifest URL of the owner in the message
+      // payload, it notifies the consumer a sync operation should be performed.
+      systemMessenger.sendMessage("datastore-update-" + aStore,
+                                  { owner: aOwner },
+                                  null,
+                                  Services.io.newURI(manifestURL, null, null));
+    }
+  },
+
+  // Use the following logic to broadcast system messages in a moderate pattern.
+  // 1. When an entry is changed, start a short timer and a long timer.
+  // 2. If an entry is changed while the short timer is running, reset it.
+  //    Do not reset the long timer.
+  // 3. Once either fires, broadcast the system message and cancel both timers.
+  setSystemMessageTimeout: function(aStore, aOwner) {
+    debug("setSystemMessageTimeout");
+
+    var storeKey = aStore + "|" + aOwner;
+    
+    // Reset the short timer.
+    var shortTimer = this.sysMsgOnChangeShortTimers[storeKey];
+    if (!shortTimer) {
+      shortTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+      this.sysMsgOnChangeShortTimers[storeKey] = shortTimer;
+    } else {
+      shortTimer.cancel();
+    }
+    shortTimer.initWithCallback({ notify: this.broadcastSystemMessage.bind(this, aStore, aOwner) },
+                                kSysMsgOnChangeShortTimeoutSec * 1000,
+                                Ci.nsITimer.TYPE_ONE_SHOT);
+
+    // Set the long timer if necessary.
+    if (!this.sysMsgOnChangeLongTimers[storeKey]) {
+      var longTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+      this.sysMsgOnChangeLongTimers[storeKey] = longTimer;
+      longTimer.initWithCallback({ notify: this.broadcastSystemMessage.bind(this, aStore, aOwner) },
+                                 kSysMsgOnChangeLongTimeoutSec * 1000,
+                                 Ci.nsITimer.TYPE_ONE_SHOT);
+    }
+  },
 
   receiveMessage: function(aMessage) {
     debug("receiveMessage ");
@@ -89,6 +174,7 @@ this.DataStoreChangeNotifier = {
     switch (aMessage.name) {
       case "DataStore:Changed":
         this.broadcastMessage(aMessage.data);
+        this.setSystemMessageTimeout(aMessage.data.store, aMessage.data.owner);
         break;
 
       case "DataStore:RegisterForMessages":
diff --git a/dom/datastore/DataStoreService.cpp b/dom/datastore/DataStoreService.cpp
index a30a513a8d7..580246bc54b 100644
--- a/dom/datastore/DataStoreService.cpp
+++ b/dom/datastore/DataStoreService.cpp
@@ -33,9 +33,11 @@
 #include "nsIDocument.h"
 #include "nsIDOMGlobalPropertyInitializer.h"
 #include "nsIIOService.h"
+#include "nsIMutableArray.h"
 #include "nsIObserverService.h"
 #include "nsIPermissionManager.h"
 #include "nsIScriptSecurityManager.h"
+#include "nsISupportsPrimitives.h"
 #include "nsIUUIDGenerator.h"
 #include "nsPIDOMWindow.h"
 #include "nsIURI.h"
@@ -375,6 +377,24 @@ GetDataStoreInfosEnumerator(const uint32_t& aAppId,
   return PL_DHASH_NEXT;
 }
 
+PLDHashOperator
+GetAppManifestURLsEnumerator(const uint32_t& aAppId,
+                             DataStoreInfo* aInfo,
+                             void* aUserData)
+{
+  AssertIsInMainProcess();
+  MOZ_ASSERT(NS_IsMainThread());
+
+  auto* manifestURLs = static_cast<nsIMutableArray*>(aUserData);
+  nsCOMPtr<nsISupportsString> manifestURL(do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID));
+  if (manifestURL) {
+    manifestURL->SetData(aInfo->mManifestURL);
+    manifestURLs->AppendElement(manifestURL, false);
+  }
+
+  return PL_DHASH_NEXT;
+}
+
 // This class is useful to enumerate the add permissions for each app.
 class MOZ_STACK_CLASS AddPermissionsData
 {
@@ -1057,6 +1077,31 @@ DataStoreService::GetDataStoreInfos(const nsAString& aName,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+DataStoreService::GetAppManifestURLsForDataStore(const nsAString& aName,
+                                                 nsIArray** aManifestURLs)
+{
+  ASSERT_PARENT_PROCESS()
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIMutableArray> manifestURLs = do_CreateInstance(NS_ARRAY_CONTRACTID);
+  if (!manifestURLs) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  HashApp* apps = nullptr;
+  if (mStores.Get(aName, &apps)) {
+    apps->EnumerateRead(GetAppManifestURLsEnumerator, manifestURLs.get());
+  }
+  if (mAccessStores.Get(aName, &apps)) {
+    apps->EnumerateRead(GetAppManifestURLsEnumerator, manifestURLs.get());
+  }
+
+  *aManifestURLs = manifestURLs;
+  NS_ADDREF(*aManifestURLs);
+  return NS_OK;
+}
+
 bool
 DataStoreService::CheckPermission(nsIPrincipal* aPrincipal)
 {
diff --git a/dom/datastore/nsIDataStoreService.idl b/dom/datastore/nsIDataStoreService.idl
index b2b3d658630..adb2b2f50ff 100644
--- a/dom/datastore/nsIDataStoreService.idl
+++ b/dom/datastore/nsIDataStoreService.idl
@@ -7,8 +7,9 @@
 
 interface nsIDOMWindow;
 interface nsIPrincipal;
+interface nsIArray;
 
-[scriptable, uuid(9b59c49a-0cd7-11e4-b096-74d02b97e723)]
+[scriptable, uuid(79944b1c-187d-11e4-abb6-74d02b97e723)]
 interface nsIDataStoreService : nsISupports
 {
   void installDataStore(in unsigned long appId,
@@ -27,5 +28,7 @@ interface nsIDataStoreService : nsISupports
                             in DOMString name,
                             in DOMString owner);
 
+  nsIArray getAppManifestURLsForDataStore(in DOMString name);
+
   boolean checkPermission(in nsIPrincipal principal);
 };
diff --git a/dom/datastore/tests/file_notify_system_message.html b/dom/datastore/tests/file_notify_system_message.html
new file mode 100644
index 00000000000..05e9153cd07
--- /dev/null
+++ b/dom/datastore/tests/file_notify_system_message.html
@@ -0,0 +1,122 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test for DataStore - notify updates with system messages</title>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+  <script type="application/javascript;version=1.7">
+
+  var gStore;
+  var gChangeId = null;
+  var gChangeOperation = null;
+  var gIsSystemMessageFired = false;
+
+  function is(a, b, msg) {
+    alert((a === b ? 'OK' : 'KO') + ' ' + msg)
+  }
+
+  function ok(a, msg) {
+    alert((a ? 'OK' : 'KO')+ ' ' + msg)
+  }
+
+  function cbError() {
+    alert('KO error');
+  }
+
+  function finish() {
+    alert('DONE');
+  }
+
+  function testGetDataStores() {
+    navigator.getDataStores('foo').then(function(stores) {
+      is(stores.length, 1, "getDataStores('foo') returns 1 element");
+      is(stores[0].name, 'foo', 'The dataStore.name is foo');
+      is(stores[0].readOnly, false, 'The dataStore foo is not in readonly');
+
+      gStore = stores[0];
+      runTest();
+    }, cbError);
+  }
+
+  function testStoreAdd(value, expectedId) {
+    gStore.add(value).then(function(id) {
+      is(id, expectedId, "store.add() is called");
+    }, cbError);
+  }
+
+  function eventListener(evt) {
+    ok(evt instanceof DataStoreChangeEvent, "DataStoreChangeEvent has been received");
+    ok(evt, "OnChangeListener is called with data");
+    is(/[0-9a-zA-Z]{8}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{12}/.test(evt.revisionId), true, "event.revisionId returns something");
+    is(evt.id, gChangeId, "OnChangeListener is called with the right ID: " + evt.id);
+    is(evt.operation, gChangeOperation, "OnChangeListener is called with the right operation:" + evt.operation + " " + gChangeOperation);
+    runTest();
+  }
+
+  function onDatastoreUpdateFoo(message) {
+    gIsSystemMessageFired = true;
+    ok(true, "System message 'datastore-update-foo' has been received");
+    runTest();
+  }
+
+  var tests = [
+    // Test for GetDataStore.
+    testGetDataStores,
+
+    // Add onchange = function.
+    function() {
+      gStore.onchange = eventListener;
+      is(gStore.onchange, eventListener, "onChange is set");
+      runTest();
+    },
+
+    // Set system message handler.
+    function() {
+      navigator.mozSetMessageHandler('datastore-update-foo', onDatastoreUpdateFoo);
+      runTest();
+    },
+
+    // Add.
+    function() { gChangeId = 1; gChangeOperation = 'added';
+                 testStoreAdd({ number: 42 }, 1); },
+
+    // Remove event listener.
+    function() {
+      gStore.removeEventListener('change', eventListener);
+      runTest();
+    },
+
+    // Wait enough amount of time for the system message to fire.
+    function() {
+      setTimeout(runTest, 10000);
+    },
+
+    // Ensure the system message has fired and no more pending ones.
+    function() {
+      ok(!navigator.mozHasPendingMessage('datastore-update-foo'), "No more pending system message");
+      ok(gIsSystemMessageFired, "The system message has fired");
+      runTest();
+    }
+  ];
+
+  function runTest() {
+    if (!tests.length) {
+      finish();
+      return;
+    }
+
+    var test = tests.shift();
+    test();
+  }
+
+  runTest();
+  </script>
+</pre>
+</body>
+</html>
diff --git a/dom/datastore/tests/mochitest.ini b/dom/datastore/tests/mochitest.ini
index fd3972597db..e1ca2818206 100644
--- a/dom/datastore/tests/mochitest.ini
+++ b/dom/datastore/tests/mochitest.ini
@@ -30,6 +30,7 @@ support-files =
   file_sync_common.js
   file_bug1008044.html
   file_bug957086.html
+  file_notify_system_message.html
 
 [test_app_install.html]
 [test_readonly.html]
@@ -50,3 +51,5 @@ support-files =
 [test_transactions.html]
 [test_bug1008044.html]
 [test_bug957086.html]
+[test_notify_system_message.html]
+skip-if = toolkit == 'gonk' # b2g
diff --git a/dom/datastore/tests/test_app_install.html b/dom/datastore/tests/test_app_install.html
index c03f249326d..8c326d33704 100644
--- a/dom/datastore/tests/test_app_install.html
+++ b/dom/datastore/tests/test_app_install.html
@@ -10,10 +10,6 @@
 <div id="container"></div>
   <script type="application/javascript;version=1.7">
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
 
   var gBaseURL = 'http://test/tests/dom/datastore/tests/';
@@ -26,8 +22,14 @@
      { "type": "webapps-manage", "allow": 1, "context": document }],
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, function() {
+
+        if (SpecialPowers.isMainProcess()) {
+          SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+        }
         gGenerator.next(); });
     });
 
diff --git a/dom/datastore/tests/test_arrays.html b/dom/datastore/tests/test_arrays.html
index a1d81a2f48b..513a6de28f6 100644
--- a/dom/datastore/tests/test_arrays.html
+++ b/dom/datastore/tests/test_arrays.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_basic.html b/dom/datastore/tests/test_basic.html
index 25d6637ef50..c774b146c9f 100644
--- a/dom/datastore/tests/test_basic.html
+++ b/dom/datastore/tests/test_basic.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_basic_worker.html b/dom/datastore/tests/test_basic_worker.html
index be940e8771b..70fadecd8fa 100644
--- a/dom/datastore/tests/test_basic_worker.html
+++ b/dom/datastore/tests/test_basic_worker.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_bug1008044.html b/dom/datastore/tests/test_bug1008044.html
index 97164c396ca..c22131f2379 100644
--- a/dom/datastore/tests/test_bug1008044.html
+++ b/dom/datastore/tests/test_bug1008044.html
@@ -77,12 +77,18 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.ipc.browser_frames.oop_by_default", true],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -117,10 +123,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_bug924104.html b/dom/datastore/tests/test_bug924104.html
index 5b22acf11db..3896a108b30 100644
--- a/dom/datastore/tests/test_bug924104.html
+++ b/dom/datastore/tests/test_bug924104.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_bug957086.html b/dom/datastore/tests/test_bug957086.html
index 1abb1f4c153..ac8f31ee09b 100644
--- a/dom/datastore/tests/test_bug957086.html
+++ b/dom/datastore/tests/test_bug957086.html
@@ -81,12 +81,18 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.ipc.browser_frames.oop_by_default", true],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -124,10 +130,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_bug976311.html b/dom/datastore/tests/test_bug976311.html
index 4922dd2db35..35f9aba480a 100644
--- a/dom/datastore/tests/test_bug976311.html
+++ b/dom/datastore/tests/test_bug976311.html
@@ -82,11 +82,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -124,10 +130,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_bug986056.html b/dom/datastore/tests/test_bug986056.html
index 2376f71483c..3d14cb666c5 100644
--- a/dom/datastore/tests/test_bug986056.html
+++ b/dom/datastore/tests/test_bug986056.html
@@ -75,12 +75,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
-    // Enabling mozBrowser
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.pushPrefEnv({"set": [["dom.mozBrowserFramesEnabled", true]]}, runTest);
     },
@@ -134,10 +139,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_certifiedApp.html b/dom/datastore/tests/test_certifiedApp.html
index 0b78ccbc814..e4a328c2d0d 100644
--- a/dom/datastore/tests/test_certifiedApp.html
+++ b/dom/datastore/tests/test_certifiedApp.html
@@ -77,6 +77,8 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", false]]}, runTest);
     },
@@ -89,6 +91,10 @@
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -123,10 +129,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_changes.html b/dom/datastore/tests/test_changes.html
index 434c4c0f4c7..c2a67b1addd 100644
--- a/dom/datastore/tests/test_changes.html
+++ b/dom/datastore/tests/test_changes.html
@@ -121,12 +121,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
-    // Enabling mozBrowser
     function() {
+   	  if (SpecialPowers.isMainProcess()) {
+   	    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+   	  }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.pushPrefEnv({"set": [["dom.mozBrowserFramesEnabled", true]]}, runTest);
     },
@@ -169,10 +174,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_duplicate.html b/dom/datastore/tests/test_duplicate.html
index e9ecca2ab9a..8589d440826 100644
--- a/dom/datastore/tests/test_duplicate.html
+++ b/dom/datastore/tests/test_duplicate.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_keys.html b/dom/datastore/tests/test_keys.html
index dced0354ef3..9bc2ac2b88b 100644
--- a/dom/datastore/tests/test_keys.html
+++ b/dom/datastore/tests/test_keys.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_notify_system_message.html b/dom/datastore/tests/test_notify_system_message.html
new file mode 100644
index 00000000000..dc32f79f5a5
--- /dev/null
+++ b/dom/datastore/tests/test_notify_system_message.html
@@ -0,0 +1,138 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test for DataStore - notify updates with system messages</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<div id="container"></div>
+  <script type="application/javascript;version=1.7">
+
+  var gHostedManifestURL = 'http://test/tests/dom/datastore/tests/file_app.sjs?testToken=file_notify_system_message.html';
+  var gHostedPageURL = 'http://mochi.test:8888/tests/dom/datastore/tests/file_notify_system_message.html';
+  var gApp;
+
+  function cbError() {
+    ok(false, "Error callback invoked");
+    finish();
+  }
+
+  function installApp() {
+    var request = navigator.mozApps.install(gHostedManifestURL);
+    request.onerror = cbError;
+    request.onsuccess = function() {
+      gApp = request.result;
+      runTest();
+    }
+  }
+
+  function uninstallApp() {
+    // Uninstall the app.
+    var request = navigator.mozApps.mgmt.uninstall(gApp);
+    request.onerror = cbError;
+    request.onsuccess = function() {
+      // All done.
+      info("All done");
+      runTest();
+    }
+  }
+
+  function testApp() {
+    var ifr = document.createElement('iframe');
+    ifr.setAttribute('mozbrowser', 'true');
+    ifr.setAttribute('mozapp', gApp.manifestURL);
+    ifr.setAttribute('src', gApp.manifest.launch_path);
+    var domParent = document.getElementById('container');
+
+    // Set us up to listen for messages from the app.
+    var listener = function(e) {
+      var message = e.detail.message;
+      if (/^OK/.exec(message)) {
+        ok(true, "Message from app: " + message);
+      } else if (/KO/.exec(message)) {
+        ok(false, "Message from app: " + message);
+      } else if (/DONE/.exec(message)) {
+        ok(true, "Messaging from app complete");
+        ifr.removeEventListener('mozbrowsershowmodalprompt', listener);
+        domParent.removeChild(ifr);
+        runTest();
+      }
+    }
+
+    // This event is triggered when the app calls "alert".
+    ifr.addEventListener('mozbrowsershowmodalprompt', listener, false);
+    domParent.appendChild(ifr);
+  }
+
+  var tests = [
+    // Permissions.
+    function() {
+      SpecialPowers.pushPermissions(
+        [{ "type": "browser", "allow": 1, "context": document },
+         { "type": "embed-apps", "allow": 1, "context": document },
+         { "type": "webapps-manage", "allow": 1, "context": document }], runTest);
+    },
+
+    // Preferences.
+    function() {
+      SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
+                                         ["dom.sysmsg.enabled", true],
+                                         ["dom.testing.ignore_ipc_principal", true],
+                                         ["dom.testing.datastore_enabled_for_hosted_apps", true],
+                                         ["dom.mozBrowserFramesEnabled", true]]}, runTest);
+    },
+
+    function() {
+      SpecialPowers.setAllAppsLaunchable(true);
+      // No confirmation needed when an app is installed.
+      SpecialPowers.autoConfirmAppInstall(runTest);
+    },
+
+    function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+        SpecialPowers.Cu.import("resource://gre/modules/Services.jsm");
+        var ioService = SpecialPowers.Cc["@mozilla.org/network/io-service;1"]
+                                     .getService(SpecialPowers.Ci.nsIIOService);
+        var systemMessenger = SpecialPowers.Cc["@mozilla.org/system-message-internal;1"]
+                              .getService(SpecialPowers.Ci.nsISystemMessagesInternal);
+        systemMessenger.registerPage("datastore-update-foo",
+                                     ioService.newURI(gHostedPageURL, null, null),
+                                     ioService.newURI(gHostedManifestURL, null, null));
+      }
+      runTest();
+    },
+
+    // Installing the app.
+    installApp,
+
+    // Run tests in app.
+    testApp,
+
+    // Uninstall the app.
+    uninstallApp
+  ];
+
+  function runTest() {
+    if (!tests.length) {
+      finish();
+      return;
+    }
+
+    var test = tests.shift();
+    test();
+  }
+
+  function finish() {
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+  runTest();
+  </script>
+</body>
+</html>
diff --git a/dom/datastore/tests/test_oop.html b/dom/datastore/tests/test_oop.html
index 989904341e6..e275b2d1b3d 100644
--- a/dom/datastore/tests/test_oop.html
+++ b/dom/datastore/tests/test_oop.html
@@ -77,12 +77,18 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.ipc.browser_frames.oop_by_default", true],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -117,10 +123,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_oop_events.html b/dom/datastore/tests/test_oop_events.html
index d97d674c8a9..c57f93de657 100644
--- a/dom/datastore/tests/test_oop_events.html
+++ b/dom/datastore/tests/test_oop_events.html
@@ -105,12 +105,18 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.ipc.browser_frames.oop_by_default", true],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -147,10 +153,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_readonly.html b/dom/datastore/tests/test_readonly.html
index 559b8d0f3eb..52541cd2618 100644
--- a/dom/datastore/tests/test_readonly.html
+++ b/dom/datastore/tests/test_readonly.html
@@ -30,6 +30,10 @@
   }
 
   function runTest() {
+    if (SpecialPowers.isMainProcess()) {
+      SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+    }
+
     SpecialPowers.setAllAppsLaunchable(true);
     SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
 
@@ -95,12 +99,10 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                     ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                     ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                      ["dom.testing.ignore_ipc_principal", true],
                                      ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
   </script>
diff --git a/dom/datastore/tests/test_sync.html b/dom/datastore/tests/test_sync.html
index b45472c88ba..15ab46c910c 100644
--- a/dom/datastore/tests/test_sync.html
+++ b/dom/datastore/tests/test_sync.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
     },
@@ -115,10 +121,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_sync_worker.html b/dom/datastore/tests/test_sync_worker.html
index 904edea96e8..4e1d5d0507f 100644
--- a/dom/datastore/tests/test_sync_worker.html
+++ b/dom/datastore/tests/test_sync_worker.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
     },
@@ -115,10 +121,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/datastore/tests/test_transactions.html b/dom/datastore/tests/test_transactions.html
index 7607b11fa5c..26d974aa1cb 100644
--- a/dom/datastore/tests/test_transactions.html
+++ b/dom/datastore/tests/test_transactions.html
@@ -77,11 +77,17 @@
     // Preferences
     function() {
       SpecialPowers.pushPrefEnv({"set": [["dom.datastore.enabled", true],
+                                         ["dom.datastore.sysMsgOnChangeShortTimeoutSec", 1],
+                                         ["dom.datastore.sysMsgOnChangeLongTimeoutSec", 3],
                                          ["dom.testing.ignore_ipc_principal", true],
                                          ["dom.testing.datastore_enabled_for_hosted_apps", true]]}, runTest);
     },
 
     function() {
+      if (SpecialPowers.isMainProcess()) {
+        SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
+      }
+
       SpecialPowers.setAllAppsLaunchable(true);
       SpecialPowers.setBoolPref("dom.mozBrowserFramesEnabled", true);
       runTest();
@@ -116,10 +122,6 @@
     SimpleTest.finish();
   }
 
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
   SimpleTest.waitForExplicitFinish();
   runTest();
   </script>
diff --git a/dom/messages/SystemMessageInternal.js b/dom/messages/SystemMessageInternal.js
index 72708689626..74e24e38129 100644
--- a/dom/messages/SystemMessageInternal.js
+++ b/dom/messages/SystemMessageInternal.js
@@ -192,31 +192,48 @@ SystemMessageInternal.prototype = {
     // clean it up from the pending message queue when apps receive it.
     let messageID = gUUIDGenerator.generateUUID().toString();
 
-    debug("Sending " + aType + " " + JSON.stringify(aMessage) +
-      " for " + aPageURI.spec + " @ " + aManifestURI.spec +
-      '; extra: ' + JSON.stringify(aExtra));
-
-    let result = this._sendMessageCommon(aType,
-                                         aMessage,
-                                         messageID,
-                                         aPageURI.spec,
-                                         aManifestURI.spec,
-                                         aExtra);
-    debug("Returned status of sending message: " + result);
-
-    // Don't need to open the pages and queue the system message
-    // which was not allowed to be sent.
-    if (result === MSG_SENT_FAILURE_PERM_DENIED) {
-      return;
+    let manifestURL = aManifestURI.spec;
+    let pageURLs = [];
+    if (aPageURI) {
+      pageURLs.push(aPageURI.spec);
+    } else {
+      // Send this message to all the registered pages of the app if |aPageURI|
+      // is not specified.
+      for (let i = 0; i < this._pages.length; i++) {
+        let page = this._pages[i];
+        if (page.type === aType && page.manifestURL === manifestURL) {
+          pageURLs.push(page.pageURL);
+        }
+      }
     }
 
-    let page = this._findPage(aType, aPageURI.spec, aManifestURI.spec);
-    if (page) {
-      // Queue this message in the corresponding pages.
-      this._queueMessage(page, aMessage, messageID);
+    pageURLs.forEach(function(aPageURL) {
+      debug("Sending " + aType + " " + JSON.stringify(aMessage) +
+        " for " + aPageURL + " @ " + manifestURL +
+        '; extra: ' + JSON.stringify(aExtra));
 
-      this._openAppPage(page, aMessage, aExtra, result);
-    }
+      let result = this._sendMessageCommon(aType,
+                                           aMessage,
+                                           messageID,
+                                           aPageURL,
+                                           manifestURL,
+                                           aExtra);
+      debug("Returned status of sending message: " + result);
+
+      // Don't need to open the pages and queue the system message
+      // which was not allowed to be sent.
+      if (result === MSG_SENT_FAILURE_PERM_DENIED) {
+        return;
+      }
+
+      let page = this._findPage(aType, aPageURL, manifestURL);
+      if (page) {
+        // Queue this message in the corresponding pages.
+        this._queueMessage(page, aMessage, messageID);
+
+        this._openAppPage(page, aMessage, aExtra, result);
+      }
+    }, this);
   },
 
   broadcastMessage: function(aType, aMessage, aExtra) {
diff --git a/dom/messages/SystemMessagePermissionsChecker.jsm b/dom/messages/SystemMessagePermissionsChecker.jsm
index 433c8759875..89bcf675734 100644
--- a/dom/messages/SystemMessagePermissionsChecker.jsm
+++ b/dom/messages/SystemMessagePermissionsChecker.jsm
@@ -15,7 +15,8 @@ Cu.import("resource://gre/modules/PermissionsTable.jsm");
 Cu.import("resource://gre/modules/PermissionSettings.jsm");
 
 this.EXPORTED_SYMBOLS = ["SystemMessagePermissionsChecker",
-                         "SystemMessagePermissionsTable"];
+                         "SystemMessagePermissionsTable",
+                         "SystemMessagePrefixPermissionsTable"];
 
 function debug(aStr) {
   // dump("SystemMessagePermissionsChecker.jsm: " + aStr + "\n");
@@ -122,6 +123,18 @@ this.SystemMessagePermissionsTable = {
   }
 };
 
+// This table maps system message prefix to permission(s), indicating only
+// the system messages with specified prefixes granted by the page's permissions
+// are allowed to be registered or sent to that page. Note the empty permission
+// set means this type of system message is always permitted.
+//
+// Note that this table is only used when the permission checker can't find a
+// match in SystemMessagePermissionsTable listed above.
+
+this.SystemMessagePrefixPermissionsTable = {
+  "datastore-update-": { },
+};
+
 this.SystemMessagePermissionsChecker = {
   /**
    * Return all the needed permission names for the given system message.
@@ -140,16 +153,26 @@ this.SystemMessagePermissionsChecker = {
 
     let permNames = SystemMessagePermissionsTable[aSysMsgName];
     if (permNames === undefined) {
-      debug("'" + aSysMsgName + "' is not associated with permissions. " +
-            "Please add them to the SystemMessagePermissionsTable.");
-      return null;
+      // Try to look up in the prefix table.
+      for (let sysMsgPrefix in SystemMessagePrefixPermissionsTable) {
+        if (aSysMsgName.indexOf(sysMsgPrefix) === 0) {
+          permNames = SystemMessagePrefixPermissionsTable[sysMsgPrefix];
+          break;
+        }
+      }
+
+      if (permNames === undefined) {
+        debug("'" + aSysMsgName + "' is not associated with permissions. " +
+              "Please add them to the SystemMessage[Prefix]PermissionsTable.");
+        return null;
+      }
     }
 
     let object = { };
     for (let permName in permNames) {
       if (PermissionsTable[permName] === undefined) {
         debug("'" + permName + "' for '" + aSysMsgName + "' is invalid. " +
-              "Please correct it in the SystemMessagePermissionsTable.");
+              "Please correct it in the SystemMessage[Prefix]PermissionsTable.");
         return null;
       }
 
@@ -157,7 +180,7 @@ this.SystemMessagePermissionsChecker = {
       let access = permNames[permName];
       if (!access || !Array.isArray(access)) {
         debug("'" + permName + "' is not associated with access array. " +
-              "Please correct it in the SystemMessagePermissionsTable.");
+              "Please correct it in the SystemMessage[Prefix]PermissionsTable.");
         return null;
       }
       object[permName] = appendAccessToPermName(permName, access);
diff --git a/dom/messages/interfaces/nsISystemMessagesInternal.idl b/dom/messages/interfaces/nsISystemMessagesInternal.idl
index 8df78278f07..450206b2ba5 100644
--- a/dom/messages/interfaces/nsISystemMessagesInternal.idl
+++ b/dom/messages/interfaces/nsISystemMessagesInternal.idl
@@ -13,10 +13,12 @@ interface nsIDOMWindow;
 interface nsISystemMessagesInternal : nsISupports
 {
   /*
-   * Allow any internal user to broadcast a message of a given type.
+   * Allow any internal user to send a message of a given type to a given page
+   * of an app. The message will be sent to all the registered pages of the app
+   * when |pageURI| is not specified.
    * @param type        The type of the message to be sent.
    * @param message     The message payload.
-   * @param pageURI     The URI of the page that will be opened.
+   * @param pageURI     The URI of the page that will be opened. Nullable.
    * @param manifestURI The webapp's manifest URI.
    * @param extra       Extra opaque information that will be passed around in the observer
    *                    notification to open the page.