diff --git a/dom/apps/src/AppsService.js b/dom/apps/src/AppsService.js
index 6ae20fcaea4..36d20a991f5 100644
--- a/dom/apps/src/AppsService.js
+++ b/dom/apps/src/AppsService.js
@@ -53,6 +53,26 @@ AppsService.prototype = {
     }
   },
 
+  getAppByLocalId: function getAppByLocalId(aLocalId) {
+    debug("getAppByLocalId( " + aLocalId + " )");
+    if (this.inParent) {
+      return DOMApplicationRegistry.getAppByLocalId(aLocalId);
+    } else {
+      return this.cpmm.sendSyncMessage("WebApps:GetAppByLocalId",
+                                       { id: aLocalId })[0];
+    }
+  },
+
+  getManifestURLByLocalId: function getManifestURLByLocalId(aLocalId) {
+    debug("getManifestURLByLocalId( " + aLocalId + " )");
+    if (this.inParent) {
+      return DOMApplicationRegistry.getManifestURLByLocalId(aLocalId);
+    } else {
+      return this.cpmm.sendSyncMessage("WebApps:GetManifestURLByLocalId",
+                                       { id: aLocalId })[0];
+    }
+  },
+
   classID : APPS_SERVICE_CID,
   QueryInterface : XPCOMUtils.generateQI([Ci.nsIAppsService])
 }
diff --git a/dom/apps/src/Webapps.jsm b/dom/apps/src/Webapps.jsm
index b19dd81de18..2b7045671c5 100644
--- a/dom/apps/src/Webapps.jsm
+++ b/dom/apps/src/Webapps.jsm
@@ -57,7 +57,8 @@ let DOMApplicationRegistry = {
                     "Webapps:GetInstalled", "Webapps:GetNotInstalled",
                     "Webapps:Launch", "Webapps:GetAll",
                     "Webapps:InstallPackage", "Webapps:GetBasePath",
-                    "WebApps:GetAppByManifestURL", "WebApps:GetAppLocalIdByManifestURL"];
+                    "WebApps:GetAppByManifestURL", "WebApps:GetAppLocalIdByManifestURL",
+                    "WebApps:GetAppByLocalId", "Webapps:GetManifestURLByLocalId"];
 
     this.messages.forEach((function(msgName) {
       ppmm.addMessageListener(msgName, this);
@@ -249,6 +250,12 @@ let DOMApplicationRegistry = {
       case "WebApps:GetAppLocalIdByManifestURL":
         return { id: this.getAppLocalIdByManifestURL(msg.url) };
         break;
+      case "WebApps:GetAppByLocalId":
+        return this.getAppByLocalId(msg.id);
+        break;
+      case "WebApps:GetManifestURLByLocalId":
+        return this.getManifestURLByLocalId(msg.id);
+        break;
     }
   },
 
@@ -698,6 +705,28 @@ let DOMApplicationRegistry = {
     return null;
   },
 
+  getAppByLocalId: function(aLocalId) {
+    for (let id in this.webapps) {
+      let app = this.webapps[id];
+      if (app.localId == aLocalId) {
+        return this._cloneAppObject(app);
+      }
+    }
+
+    return null;
+  },
+
+  getManifestURLByLocalId: function(aLocalId) {
+    for (let id in this.webapps) {
+      let app = this.webapps[id];
+      if (app.localId == aLocalId) {
+        return app.manifestURL;
+      }
+    }
+
+    return null;
+  },
+
   getAppLocalIdByManifestURL: function(aManifestURL) {
     for (let id in this.webapps) {
       if (this.webapps[id].manifestURL == aManifestURL) {
diff --git a/dom/interfaces/apps/nsIAppsService.idl b/dom/interfaces/apps/nsIAppsService.idl
index 67471e7b6ef..e1559aa0e6b 100644
--- a/dom/interfaces/apps/nsIAppsService.idl
+++ b/dom/interfaces/apps/nsIAppsService.idl
@@ -15,7 +15,7 @@ interface mozIDOMApplication;
  * This service allows accessing some DOMApplicationRegistry methods from
  * non-javascript code.
  */
-[scriptable, uuid(1210a0f3-add3-4381-b892-9c102e3afc42)]
+[scriptable, uuid(04e4ef3c-1a30-45bc-ab08-291820f13872)]
 interface nsIAppsService : nsISupports
 {
   mozIDOMApplication getAppByManifestURL(in DOMString manifestURL);
@@ -27,4 +27,14 @@ interface nsIAppsService : nsISupports
    * installed manifest URL.
    */
   unsigned long getAppLocalIdByManifestURL(in DOMString manifestURL);
+
+  /**
+   * Returns the application associated to this localId.
+   */
+  mozIDOMApplication getAppByLocalId(in unsigned long localId);
+
+  /**
+   * Returns the manifest URL associated to this localId.
+   */
+  DOMString getManifestURLByLocalId(in unsigned long localId);
 };