new file mode 100644
--- /dev/null
+++ b/widget/android/AndroidAlerts.cpp
@@ -0,0 +1,102 @@
+/* -*- Mode: c++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 4; -*- */
+/* 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/. */
+
+#include "AndroidAlerts.h"
+#include "GeneratedJNIWrappers.h"
+#include "nsAlertsUtils.h"
+#include "nsAppShell.h"
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(AndroidAlerts, nsIAlertsService)
+
+NS_IMETHODIMP
+AndroidAlerts::ShowAlertNotification(const nsAString & aImageUrl,
+                                     const nsAString & aAlertTitle,
+                                     const nsAString & aAlertText,
+                                     bool aAlertTextClickable,
+                                     const nsAString & aAlertCookie,
+                                     nsIObserver * aAlertListener,
+                                     const nsAString & aAlertName,
+                                     const nsAString & aBidi,
+                                     const nsAString & aLang,
+                                     const nsAString & aData,
+                                     nsIPrincipal * aPrincipal,
+                                     bool aInPrivateBrowsing)
+{
+    MOZ_ASSERT_UNREACHABLE("Should be implemented by nsAlertsService.");
+    return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+AndroidAlerts::ShowAlert(nsIAlertNotification* aAlert,
+                         nsIObserver* aAlertListener)
+{
+    return ShowPersistentNotification(EmptyString(), aAlert, aAlertListener);
+}
+
+NS_IMETHODIMP
+AndroidAlerts::ShowPersistentNotification(const nsAString& aPersistentData,
+                                          nsIAlertNotification* aAlert,
+                                          nsIObserver* aAlertListener)
+{
+    // nsAlertsService disables our alerts backend if we ever return failure
+    // here. To keep the backend enabled, we always return NS_OK even if we
+    // encounter an error here.
+    nsresult rv;
+
+    nsAutoString imageUrl;
+    rv = aAlert->GetImageURL(imageUrl);
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+
+    nsAutoString title;
+    rv = aAlert->GetTitle(title);
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+
+    nsAutoString text;
+    rv = aAlert->GetText(text);
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+
+    nsAutoString cookie;
+    rv = aAlert->GetCookie(cookie);
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+
+    nsAutoString name;
+    rv = aAlert->GetName(name);
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+
+    nsCOMPtr<nsIPrincipal> principal;
+    rv = aAlert->GetPrincipal(getter_AddRefs(principal));
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+
+    nsAutoString host;
+    nsAlertsUtils::GetSourceHostPort(principal, host);
+
+    if (!aPersistentData.IsEmpty()) {
+        java::GeckoAppShell::ShowPersistentAlertNotificationWrapper(
+                aPersistentData, imageUrl, title, text, cookie, name, host);
+    } else {
+        if (aAlertListener) {
+            // This will remove any observers already registered for this id
+            nsAppShell::PostEvent(AndroidGeckoEvent::MakeAddObserver(name, aAlertListener));
+        }
+
+        java::GeckoAppShell::ShowAlertNotificationWrapper(
+               imageUrl, title, text, cookie, name, host);
+    }
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+AndroidAlerts::CloseAlert(const nsAString& aAlertName,
+                          nsIPrincipal* aPrincipal)
+{
+    java::GeckoAppShell::CloseNotification(aAlertName);
+    return NS_OK;
+}
+
+} // namespace widget
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/widget/android/AndroidAlerts.h
@@ -0,0 +1,29 @@
+/* -*- Mode: c++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 4; -*- */
+/* 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/. */
+
+#ifndef mozilla_widget_AndroidAlerts_h__
+#define mozilla_widget_AndroidAlerts_h__
+
+#include "nsIAlertsService.h"
+
+namespace mozilla {
+namespace widget {
+
+class AndroidAlerts : public nsIAlertsService
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIALERTSSERVICE
+
+  AndroidAlerts() {}
+
+protected:
+  virtual ~AndroidAlerts() {}
+};
+
+} // namespace widget
+} // namespace mozilla
+
+#endif // nsAndroidAlerts_h__

--- a/widget/android/moz.build
+++ b/widget/android/moz.build
@@ -19,16 +19,17 @@ EXPORTS += [
     'AndroidBridge.h',
     'AndroidJavaWrappers.h',
     'AndroidJNIWrapper.h',
     'GeneratedJNINatives.h',
     'GeneratedJNIWrappers.h',
 ]
 
 UNIFIED_SOURCES += [
+    'AndroidAlerts.cpp',
     'AndroidBridge.cpp',
     'AndroidContentController.cpp',
     'AndroidDirectTexture.cpp',
     'AndroidGraphicBuffer.cpp',
     'AndroidJavaWrappers.cpp',
     'AndroidJNI.cpp',
     'AndroidJNIWrapper.cpp',
     'ANRReporter.cpp',

--- a/widget/android/nsWidgetFactory.cpp
+++ b/widget/android/nsWidgetFactory.cpp
@@ -22,16 +22,19 @@
 #include "nsTransferable.h"
 #include "nsPrintOptionsAndroid.h"
 #include "nsPrintSession.h"
 #include "nsDeviceContextAndroid.h"
 #include "nsHTMLFormatConverter.h"
 #include "nsXULAppAPI.h"
 #include "nsAndroidProtocolHandler.h"
 
+#include "nsToolkitCompsCID.h"
+#include "AndroidAlerts.h"
+
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsWindow)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsScreenManagerAndroid)
 NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(nsIdleServiceAndroid, nsIdleServiceAndroid::GetInstance)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsTransferable)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsClipboard)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsClipboardHelper)
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsPrintOptionsAndroid, Init)
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsPrintSession, Init)
@@ -40,16 +43,17 @@ NS_GENERIC_FACTORY_CONSTRUCTOR(nsHTMLFor
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsAndroidBridge)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsAndroidProtocolHandler)
 
 #include "GfxInfo.h"
 namespace mozilla {
 namespace widget {
 // This constructor should really be shared with all platforms.
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(GfxInfo, Init)
+NS_GENERIC_FACTORY_CONSTRUCTOR(AndroidAlerts)
 }
 }
 
 NS_DEFINE_NAMED_CID(NS_APPSHELL_CID);
 NS_DEFINE_NAMED_CID(NS_WINDOW_CID);
 NS_DEFINE_NAMED_CID(NS_CHILD_CID);
 NS_DEFINE_NAMED_CID(NS_SCREENMANAGER_CID);
 NS_DEFINE_NAMED_CID(NS_IDLE_SERVICE_CID);
@@ -58,16 +62,17 @@ NS_DEFINE_NAMED_CID(NS_CLIPBOARD_CID);
 NS_DEFINE_NAMED_CID(NS_CLIPBOARDHELPER_CID);
 NS_DEFINE_NAMED_CID(NS_PRINTSETTINGSSERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_PRINTSESSION_CID);
 NS_DEFINE_NAMED_CID(NS_DEVICE_CONTEXT_SPEC_CID);
 NS_DEFINE_NAMED_CID(NS_HTMLFORMATCONVERTER_CID);
 NS_DEFINE_NAMED_CID(NS_GFXINFO_CID);
 NS_DEFINE_NAMED_CID(NS_ANDROIDBRIDGE_CID);
 NS_DEFINE_NAMED_CID(NS_ANDROIDPROTOCOLHANDLER_CID);
+NS_DEFINE_NAMED_CID(NS_SYSTEMALERTSSERVICE_CID);
 
 static const mozilla::Module::CIDEntry kWidgetCIDs[] = {
   { &kNS_WINDOW_CID, false, nullptr, nsWindowConstructor },
   { &kNS_CHILD_CID, false, nullptr, nsWindowConstructor },
   { &kNS_APPSHELL_CID, false, nullptr, nsAppShellConstructor },
   { &kNS_SCREENMANAGER_CID, false, nullptr, nsScreenManagerAndroidConstructor },
   { &kNS_IDLE_SERVICE_CID, false, nullptr, nsIdleServiceAndroidConstructor },
   { &kNS_TRANSFERABLE_CID, false, nullptr, nsTransferableConstructor },
@@ -75,16 +80,17 @@ static const mozilla::Module::CIDEntry k
   { &kNS_CLIPBOARDHELPER_CID, false, nullptr, nsClipboardHelperConstructor },
   { &kNS_PRINTSETTINGSSERVICE_CID, false, nullptr, nsPrintOptionsAndroidConstructor },
   { &kNS_PRINTSESSION_CID, false, nullptr, nsPrintSessionConstructor },
   { &kNS_DEVICE_CONTEXT_SPEC_CID, false, nullptr, nsDeviceContextSpecAndroidConstructor },
   { &kNS_HTMLFORMATCONVERTER_CID, false, nullptr, nsHTMLFormatConverterConstructor },
   { &kNS_GFXINFO_CID, false, nullptr, mozilla::widget::GfxInfoConstructor },
   { &kNS_ANDROIDBRIDGE_CID, false, nullptr, nsAndroidBridgeConstructor },
   { &kNS_ANDROIDPROTOCOLHANDLER_CID, false, nullptr, nsAndroidProtocolHandlerConstructor },
+  { &kNS_SYSTEMALERTSSERVICE_CID, false, nullptr, mozilla::widget::AndroidAlertsConstructor },
   { nullptr }
 };
 
 static const mozilla::Module::ContractIDEntry kWidgetContracts[] = {
   { "@mozilla.org/widgets/window/android;1", &kNS_WINDOW_CID },
   { "@mozilla.org/widgets/child_window/android;1", &kNS_CHILD_CID },
   { "@mozilla.org/widget/appshell/android;1", &kNS_APPSHELL_CID },
   { "@mozilla.org/gfx/screenmanager;1", &kNS_SCREENMANAGER_CID },
@@ -94,16 +100,17 @@ static const mozilla::Module::ContractID
   { "@mozilla.org/widget/clipboardhelper;1", &kNS_CLIPBOARDHELPER_CID },
   { "@mozilla.org/gfx/printsettings-service;1", &kNS_PRINTSETTINGSSERVICE_CID },
   { "@mozilla.org/gfx/printsession;1", &kNS_PRINTSESSION_CID },
   { "@mozilla.org/gfx/devicecontextspec;1", &kNS_DEVICE_CONTEXT_SPEC_CID },
   { "@mozilla.org/widget/htmlformatconverter;1", &kNS_HTMLFORMATCONVERTER_CID },
   { "@mozilla.org/gfx/info;1", &kNS_GFXINFO_CID },
   { "@mozilla.org/android/bridge;1", &kNS_ANDROIDBRIDGE_CID },
   { NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX "android", &kNS_ANDROIDPROTOCOLHANDLER_CID },
+  { NS_SYSTEMALERTSERVICE_CONTRACTID, &kNS_SYSTEMALERTSSERVICE_CID },
   { nullptr }
 };
 
 static void
 nsWidgetAndroidModuleDtor()
 {
     // Shutdown all XP level widget classes.
     mozilla::widget::WidgetUtils::Shutdown();