diff --git a/content/base/public/nsIFrameLoader.idl b/content/base/public/nsIFrameLoader.idl
index 4e91d82e351..9f3c21c2778 100644
--- a/content/base/public/nsIFrameLoader.idl
+++ b/content/base/public/nsIFrameLoader.idl
@@ -288,7 +288,6 @@ interface nsIFrameLoader : nsISupports
 
   /**
    * Find out whether the owner content really is a browser or app frame
-   * Especially, a widget frame is regarded as an app frame.
    */
   readonly attribute boolean ownerIsBrowserOrAppFrame;
 };
diff --git a/content/base/src/nsGkAtomList.h b/content/base/src/nsGkAtomList.h
index c3c9d9a0ab8..561a628e36f 100644
--- a/content/base/src/nsGkAtomList.h
+++ b/content/base/src/nsGkAtomList.h
@@ -91,7 +91,6 @@ GK_ATOM(_and, "and")
 GK_ATOM(anonid, "anonid")
 GK_ATOM(any, "any")
 GK_ATOM(mozapp, "mozapp")
-GK_ATOM(mozwidget, "mozwidget")
 GK_ATOM(applet, "applet")
 GK_ATOM(applyImports, "apply-imports")
 GK_ATOM(applyTemplates, "apply-templates")
diff --git a/content/html/content/src/nsGenericHTMLFrameElement.cpp b/content/html/content/src/nsGenericHTMLFrameElement.cpp
index a015675c726..e700f01c0e0 100644
--- a/content/html/content/src/nsGenericHTMLFrameElement.cpp
+++ b/content/html/content/src/nsGenericHTMLFrameElement.cpp
@@ -332,63 +332,6 @@ nsGenericHTMLFrameElement::GetIsExpectingSystemMessage(bool *aOut)
   return NS_OK;
 }
 
-/** Get manifest url of app or widget
- * @param AppType: nsGkAtoms::mozapp or nsGkAtoms::mozwidget
- */
-void nsGenericHTMLFrameElement::GetManifestURLByType(nsIAtom *aAppType,
-                                                     nsAString& aManifestURL)
-{
-  aManifestURL.Truncate();
-
-  if (aAppType != nsGkAtoms::mozapp && aAppType != nsGkAtoms::mozwidget) {
-    return;
-  }
-
-  nsAutoString manifestURL;
-  GetAttr(kNameSpaceID_None, aAppType, manifestURL);
-  if (manifestURL.IsEmpty()) {
-    return;
-  }
-
-  // Check permission.
-  nsCOMPtr<nsIPermissionManager> permMgr = services::GetPermissionManager();
-  NS_ENSURE_TRUE_VOID(permMgr);
-  nsIPrincipal *principal = NodePrincipal();
-  const char* aPermissionType = (aAppType == nsGkAtoms::mozapp) ? "embed-apps"
-                                                                : "embed-widgets";
-  uint32_t permission = nsIPermissionManager::DENY_ACTION;
-  nsresult rv = permMgr->TestPermissionFromPrincipal(principal,
-                                                     aPermissionType,
-                                                     &permission);
-  NS_ENSURE_SUCCESS_VOID(rv);
-  if (permission != nsIPermissionManager::ALLOW_ACTION) {
-    return;
-  }
-
-  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
-  NS_ENSURE_TRUE_VOID(appsService);
-
-  nsCOMPtr<mozIApplication> app;
-  appsService->GetAppByManifestURL(manifestURL, getter_AddRefs(app));
-
-  if (!app) {
-    return;
-  }
-
-  bool hasWidgetPage = false;
-  nsAutoString src;
-  if (aAppType == nsGkAtoms::mozwidget) {
-    GetAttr(kNameSpaceID_None, nsGkAtoms::src, src);
-    nsresult rv = app->HasWidgetPage(src, &hasWidgetPage);
-
-    if (!NS_SUCCEEDED(rv) || !hasWidgetPage) {
-      return;
-    }
-  }
-
-  aManifestURL.Assign(manifestURL);
-}
-
 NS_IMETHODIMP
 nsGenericHTMLFrameElement::GetAppManifestURL(nsAString& aOut)
 {
@@ -399,36 +342,35 @@ nsGenericHTMLFrameElement::GetAppManifestURL(nsAString& aOut)
     return NS_OK;
   }
 
-  nsAutoString appManifestURL;
-  nsAutoString widgetManifestURL;
+  // Check permission.
+  nsIPrincipal *principal = NodePrincipal();
+  nsCOMPtr<nsIPermissionManager> permMgr =
+    services::GetPermissionManager();
+  NS_ENSURE_TRUE(permMgr, NS_OK);
 
-  GetManifestURLByType(nsGkAtoms::mozapp, appManifestURL);
-
-  if (Preferences::GetBool("dom.enable_widgets")) {
-    GetManifestURLByType(nsGkAtoms::mozwidget, widgetManifestURL);
-  }
-
-  bool isApp = !appManifestURL.IsEmpty();
-  bool isWidget = !widgetManifestURL.IsEmpty();
-
-  if (!isApp && !isWidget) {
-    // No valid case to get manifest
-    return NS_OK;
-  }
-
-  if (isApp && isWidget) {
-    NS_WARNING("Can not simultaneously be mozapp and mozwidget");
+  uint32_t permission = nsIPermissionManager::DENY_ACTION;
+  nsresult rv = permMgr->TestPermissionFromPrincipal(principal,
+                                                     "embed-apps",
+                                                     &permission);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+  if (permission != nsIPermissionManager::ALLOW_ACTION) {
     return NS_OK;
   }
 
   nsAutoString manifestURL;
-  if (isApp) {
-    manifestURL.Assign(appManifestURL);
-  } else if (isWidget) {
-    manifestURL.Assign(widgetManifestURL);
+  GetAttr(kNameSpaceID_None, nsGkAtoms::mozapp, manifestURL);
+  if (manifestURL.IsEmpty()) {
+    return NS_OK;
   }
 
-  aOut.Assign(manifestURL);
+  nsCOMPtr<nsIAppsService> appsService = do_GetService(APPS_SERVICE_CONTRACTID);
+  NS_ENSURE_TRUE(appsService, NS_OK);
+
+  nsCOMPtr<mozIApplication> app;
+  appsService->GetAppByManifestURL(manifestURL, getter_AddRefs(app));
+  if (app) {
+    aOut.Assign(manifestURL);
+  }
 
   return NS_OK;
 }
diff --git a/content/html/content/src/nsGenericHTMLFrameElement.h b/content/html/content/src/nsGenericHTMLFrameElement.h
index de3fe18a393..8f7386e916d 100644
--- a/content/html/content/src/nsGenericHTMLFrameElement.h
+++ b/content/html/content/src/nsGenericHTMLFrameElement.h
@@ -88,9 +88,6 @@ protected:
   {
     return this;
   }
-
-private:
-  void GetManifestURLByType(nsIAtom *aAppType, nsAString& aOut);
 };
 
 #endif // nsGenericHTMLFrameElement_h
diff --git a/dom/apps/src/AppsUtils.jsm b/dom/apps/src/AppsUtils.jsm
index c903387b734..097a00b1b50 100644
--- a/dom/apps/src/AppsUtils.jsm
+++ b/dom/apps/src/AppsUtils.jsm
@@ -57,10 +57,6 @@ mozIApplication.prototype = {
     return (perm === Ci.nsIPermissionManager.ALLOW_ACTION);
   },
 
-  hasWidgetPage: function(aPageURL) {
-    return this.widgetPages.indexOf(aPageURL) != -1;
-  },
-
   QueryInterface: function(aIID) {
     if (aIID.equals(Ci.mozIApplication) ||
         aIID.equals(Ci.nsISupports))
@@ -104,7 +100,6 @@ function _setAppProperties(aObj, aApp) {
   aObj.storeVersion = aApp.storeVersion || 0;
   aObj.role = aApp.role || "";
   aObj.redirects = aApp.redirects;
-  aObj.widgetPages = aApp.widgetPages || [];
   aObj.kind = aApp.kind;
 }
 
@@ -683,10 +678,6 @@ ManifestHelper.prototype = {
     return this._localeProp("package_path");
   },
 
-  get widgetPages() {
-    return this._localeProp("widgetPages");
-  },
-
   get size() {
     return this._manifest["size"] || 0;
   },
diff --git a/dom/apps/src/PermissionsTable.jsm b/dom/apps/src/PermissionsTable.jsm
index 2b09c8277f6..dfed59b8efd 100644
--- a/dom/apps/src/PermissionsTable.jsm
+++ b/dom/apps/src/PermissionsTable.jsm
@@ -232,11 +232,6 @@ this.PermissionsTable =  { geolocation: {
                              privileged: DENY_ACTION,
                              certified: ALLOW_ACTION
                            },
-                           "embed-widgets": {
-                             app: DENY_ACTION,
-                             privileged: ALLOW_ACTION,
-                             certified: ALLOW_ACTION
-                           },
                            "storage": {
                              app: ALLOW_ACTION,
                              privileged: ALLOW_ACTION,
diff --git a/dom/apps/src/Webapps.jsm b/dom/apps/src/Webapps.jsm
index f9a35e6c488..d92f14fbc0d 100755
--- a/dom/apps/src/Webapps.jsm
+++ b/dom/apps/src/Webapps.jsm
@@ -262,10 +262,6 @@ this.DOMApplicationRegistry = {
           app.role = "";
         }
 
-        if (app.widgetPages === undefined) {
-          app.widgetPages = [];
-        }
-
         // At startup we can't be downloading, and the $TMP directory
         // will be empty so we can't just apply a staged update.
         app.downloading = false;
@@ -325,15 +321,6 @@ this.DOMApplicationRegistry = {
     return res.length > 0 ? res : null;
   },
 
-  _saveWidgetsFullPath: function(aManifest, aDestApp) {
-    if (aManifest.widgetPages) {
-      aDestApp.widgetPages = aManifest.widgetPages.map(aManifest.resolveURL,
-                                                       aManifest/* thisArg */);
-    } else {
-      aDestApp.widgetPages = [];
-    }
-  },
-
   // Registers all the activities and system messages.
   registerAppsHandlers: Task.async(function*(aRunUpdate) {
     this.notifyAppsRegistryStart();
@@ -358,10 +345,6 @@ this.DOMApplicationRegistry = {
         let app = this.webapps[aResult.id];
         app.csp = aResult.manifest.csp || "";
         app.role = aResult.manifest.role || "";
-
-        let localeManifest = new ManifestHelper(aResult.manifest, app.origin, app.manifestURL);
-        this._saveWidgetsFullPath(localeManifest, app);
-
         if (app.appStatus >= Ci.nsIPrincipal.APP_STATUS_PRIVILEGED) {
           app.redirects = this.sanitizeRedirects(aResult.redirects);
         }
@@ -1001,8 +984,6 @@ this.DOMApplicationRegistry = {
         app.name = manifest.name;
         app.csp = manifest.csp || "";
         app.role = localeManifest.role;
-        this._saveWidgetsFullPath(localeManifest, app);
-
         if (app.appStatus >= Ci.nsIPrincipal.APP_STATUS_PRIVILEGED) {
           app.redirects = this.sanitizeRedirects(manifest.redirects);
         }
@@ -2033,8 +2014,6 @@ this.DOMApplicationRegistry = {
     aApp.downloadAvailable = true;
     aApp.downloadSize = manifest.size;
     aApp.updateManifest = aNewManifest;
-    this._saveWidgetsFullPath(manifest, aApp);
-
     yield this._saveApps();
 
     this.broadcastMessage("Webapps:UpdateState", {
@@ -2093,7 +2072,6 @@ this.DOMApplicationRegistry = {
       aApp.name = aNewManifest.name;
       aApp.csp = manifest.csp || "";
       aApp.role = manifest.role || "";
-      this._saveWidgetsFullPath(manifest, aApp);
       aApp.updateTime = Date.now();
     } else {
       manifest =
@@ -2493,7 +2471,6 @@ this.DOMApplicationRegistry = {
     appObject.name = aManifest.name;
     appObject.csp = aLocaleManifest.csp || "";
     appObject.role = aLocaleManifest.role;
-    this._saveWidgetsFullPath(aLocaleManifest, appObject);
     appObject.installerAppId = aData.appId;
     appObject.installerIsBrowser = aData.isBrowser;
 
@@ -2529,9 +2506,6 @@ this.DOMApplicationRegistry = {
 
     app.csp = aManifest.csp || "";
 
-    let aLocaleManifest = new ManifestHelper(aManifest, app.origin, app.manifestURL);
-    this._saveWidgetsFullPath(aLocaleManifest, app);
-
     app.appStatus = AppsUtils.getAppManifestStatus(aManifest);
 
     app.removable = true;
diff --git a/dom/apps/tests/file_app.sjs b/dom/apps/tests/file_app.sjs
index cef10bd3ae3..fe6164724d0 100644
--- a/dom/apps/tests/file_app.sjs
+++ b/dom/apps/tests/file_app.sjs
@@ -1,7 +1,6 @@
 var gBasePath = "tests/dom/apps/tests/";
 var gAppTemplatePath = "tests/dom/apps/tests/file_app.template.html";
 var gAppcacheTemplatePath = "tests/dom/apps/tests/file_cached_app.template.appcache";
-var gWidgetTemplatePath = "tests/dom/apps/tests/file_widget_app.template.html";
 var gDefaultIcon = "default_icon";
 
 function makeResource(templatePath, version, apptype) {
@@ -15,6 +14,7 @@ function makeResource(templatePath, version, apptype) {
   if (templatePath == gAppTemplatePath && apptype == 'cached') {
     res = res.replace('<html>', '<html manifest="file_app.sjs?apptype=cached&getappcache=true">');
   }
+
   return res;
 }
 
@@ -46,7 +46,7 @@ function handleRequest(request, response) {
 
   // Get the app type.
   var apptype = query.apptype;
-  if (apptype != 'hosted' && apptype != 'cached' && apptype != 'widget')
+  if (apptype != 'hosted' && apptype != 'cached')
     throw "Invalid app type: " + apptype;
 
   // Get the version from server state and handle the etag.
@@ -83,12 +83,7 @@ function handleRequest(request, response) {
     response.write(makeResource(gAppcacheTemplatePath, version, apptype));
     return;
   }
-  else if (apptype == 'widget')
-  {
-    response.setHeader("Content-Type", "text/html", false);
-    response.write(makeResource(gWidgetTemplatePath, version, apptype));
-    return;
-  }
+
   // Generate the app.
   response.setHeader("Content-Type", "text/html", false);
   response.write(makeResource(gAppTemplatePath, version, apptype));
diff --git a/dom/apps/tests/file_widget_app.template.html b/dom/apps/tests/file_widget_app.template.html
deleted file mode 100644
index 661e2c5d8a0..00000000000
--- a/dom/apps/tests/file_widget_app.template.html
+++ /dev/null
@@ -1,68 +0,0 @@
-<html>
-<head>
-<script>
-
-function sendMessage(msg) {
-  alert(msg);
-}
-
-function ok(p, msg) {
-  if (p)
-    sendMessage("OK: " + msg);
-  else
-    sendMessage("KO: " + msg);
-}
-
-function is(a, b, msg) {
-  if (a == b)
-    sendMessage("OK: " + a + " == " + b + " - " + msg);
-  else
-    sendMessage("KO: " + a + " != " + b + " - " + msg);
-}
-
-function installed(p) {
-  if (p)
-    sendMessage("IS_INSTALLED");
-  else
-    sendMessage("NOT_INSTALLED");
-}
-
-function finish() {
-  sendMessage("VERSION: MyWebApp vVERSIONTOKEN");
-  sendMessage("DONE");
-}
-
-function cbError() {
-  ok(false, "Error callback invoked");
-  finish();
-}
-
-function go() {
-  ok(true, "Launched app");
-  var request = window.navigator.mozApps.getSelf();
-  request.onsuccess = function() {
-    var widget = request.result;
-    ok(widget,"Should be a widget");
-    checkWidget(widget);
-  }
-  request.onerror = cbError;
-}
-
-function checkWidget(widget) {
-  // If the widget is installed, |widget| will be non-null. If it is, verify its state.
-  installed(!!widget);
-  if (widget) {
-    var widgetName = "Really Rapid Release (APPTYPETOKEN)";
-    var manifest = SpecialPowers.wrap(widget.manifest);
-    is(manifest.name, widgetName, "Manifest name should be correct");
-    is(widget.origin, "http://test", "Widget origin should be correct");
-    is(widget.installOrigin, "http://mochi.test:8888", "Install origin should be correct");
-  }
-  finish();
-}
-
-</script>
-</head>
-<body onload="go();">
-App Body. Version: VERSIONTOKEN
-</body></html>
diff --git a/dom/apps/tests/file_widget_app.template.webapp b/dom/apps/tests/file_widget_app.template.webapp
deleted file mode 100644
index 7990043392f..00000000000
--- a/dom/apps/tests/file_widget_app.template.webapp
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "name": "Really Rapid Release (widget)",
-  "description": "Updated even faster than <a href='http://mozilla.org'>Firefox</a>, just to annoy slashdotters.",
-  "launch_path": "/tests/dom/apps/tests/file_app.sjs?apptype=widget",
-  "icons": {
-    "128": "ICONTOKEN"
-  },
-  "widgetPages": [
-    "/tests/dom/apps/tests/file_app.sjs?apptype=widget"
-  ]
-}
diff --git a/dom/apps/tests/mochitest.ini b/dom/apps/tests/mochitest.ini
index e5f55fd78c2..8b67d343d11 100644
--- a/dom/apps/tests/mochitest.ini
+++ b/dom/apps/tests/mochitest.ini
@@ -10,8 +10,6 @@ support-files =
   file_packaged_app.sjs
   file_packaged_app.template.html
   file_packaged_app.template.webapp
-  file_widget_app.template.webapp
-  file_widget_app.template.html
   signed_app.sjs
   signed_app_template.webapp
   signed/*
@@ -30,4 +28,3 @@ skip-if = buildapp == "b2g" || toolkit == "android" # see bug 989806
 [test_receipt_operations.html]
 [test_signed_pkg_install.html]
 [test_uninstall_errors.html]
-[test_widget.html]
diff --git a/dom/apps/tests/test_widget.html b/dom/apps/tests/test_widget.html
deleted file mode 100644
index a4292c0a58d..00000000000
--- a/dom/apps/tests/test_widget.html
+++ /dev/null
@@ -1,127 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <meta charset="utf-8">
-  <title>Test for DataStore - basic operation on a readonly db</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 gWidgetManifestURL = 'http://test/tests/dom/apps/tests/file_app.sjs?apptype=widget&getmanifest=true';
-  var gApp;
-
-  function cbError() {
-    ok(false, "Error callback invoked");
-    finish();
-  }
-
-  function installApp() {
-    var request = navigator.mozApps.install(gWidgetManifestURL);
-    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('mozwidget', gApp.manifestURL);
-    ifr.setAttribute('src', gApp.origin+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 widget: " + message);
-      } else if (/KO/.exec(message)) {
-        ok(false, "Message from widget: " + message);
-      } else if (/DONE/.exec(message)) {
-        ok(true, "Message from widget 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-widgets", "allow": 1, "context": document },
-         { "type": "webapps-manage", "allow": 1, "context": document }], runTest);
-    },
-
-    // Preferences
-    function() {
-      SpecialPowers.pushPrefEnv({"set": [["dom.mozBrowserFramesEnabled", true],
-                                         ["dom.enable_widgets", true]]}, runTest);
-    },
-
-    function() {
-      SpecialPowers.setAllAppsLaunchable(true);
-      runTest();
-    },
-
-    // No confirmation needed when an app is installed
-    function() {
-      SpecialPowers.autoConfirmAppInstall(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();
-  }
-
-  if (SpecialPowers.isMainProcess()) {
-    SpecialPowers.Cu.import("resource://gre/modules/DataStoreChangeNotifier.jsm");
-  }
-
-  SimpleTest.waitForExplicitFinish();
-  runTest();
-  </script>
-</body>
-</html>
diff --git a/dom/interfaces/apps/mozIApplication.idl b/dom/interfaces/apps/mozIApplication.idl
index 4dfc6e68e07..ddc7c99797a 100644
--- a/dom/interfaces/apps/mozIApplication.idl
+++ b/dom/interfaces/apps/mozIApplication.idl
@@ -11,18 +11,12 @@
  * We expose Gecko-internal helpers related to "web apps" through this
  * sub-interface.
  */
-[scriptable, uuid(1d856b11-ac29-47d3-bd52-a86e3d45fcf4)]
+[scriptable, uuid(7bd62430-c374-49eb-be1b-ce821a180360)]
 interface mozIApplication: nsISupports
 {
   /* Return true if this app has |permission|. */
   boolean hasPermission(in string permission);
 
-  /**
-   *  Return true if this app can be a widget and
-   *  its |widgetPages| contains |page|
-   */
-  boolean hasWidgetPage(in DOMString pageURL);
-
   /* Application status as defined in nsIPrincipal. */
   readonly attribute unsigned short appStatus;
 
diff --git a/dom/interfaces/html/nsIMozBrowserFrame.idl b/dom/interfaces/html/nsIMozBrowserFrame.idl
index 19783e1fa52..fedbec09333 100644
--- a/dom/interfaces/html/nsIMozBrowserFrame.idl
+++ b/dom/interfaces/html/nsIMozBrowserFrame.idl
@@ -25,11 +25,8 @@ interface nsIMozBrowserFrame : nsIDOMMozBrowserFrame
    * Gets whether this frame really is an app frame.
    *
    * In order to really be an app frame, this frame must really be a browser
-   * frame (this requirement will go away eventually), and must satisfy one
-   * and only one of the following conditions:
-   * 1. the frame's mozapp attribute must point to the manifest of a valid app
-   * 2. the frame's mozwidget attribute must point to the manifest of a valid
-   * app, and the src should be in the |widgetPages| specified by the manifest.
+   * frame (this requirement will go away eventually), and the frame's mozapp
+   * attribute must point to the manifest of a valid app.
    */
   [infallible] readonly attribute boolean reallyIsApp;
 
@@ -44,8 +41,7 @@ interface nsIMozBrowserFrame : nsIDOMMozBrowserFrame
   [infallible] readonly attribute boolean isExpectingSystemMessage;
 
   /**
-   * Gets this frame's app manifest URL or widget manifest URL, if the frame
-   * really is an app frame.
+   * Gets this frame's app manifest URL, if the frame really is an app frame.
    * Otherwise, returns the empty string.
    *
    * This method is guaranteed not to fail.