--- a/mobile/android/base/GeckoAppShell.java
+++ b/mobile/android/base/GeckoAppShell.java
@@ -1581,17 +1581,16 @@ public class GeckoAppShell
                 return LINK_TYPE_4G; // 3.9G
             case TelephonyManager.NETWORK_TYPE_UNKNOWN:
             default:
                 Log.w(LOGTAG, "Connected to an unknown mobile network!");
                 return LINK_TYPE_UNKNOWN;
         }
     }
 
-    @WrapElementForJNI
     public static void setSelectedLocale(String localeCode) {
         /* Bug 713464: This method is still called from Gecko side.
            Earlier we had an option to run Firefox in a language other than system's language.
            However, this is not supported as of now.
            Gecko resets the locale to en-US by calling this function with an empty string.
            This affects GeckoPreferences activity in multi-locale builds.
 
         N.B., if this code ever becomes live again, you need to hook it up to locale

--- a/widget/android/GeneratedJNIWrappers.cpp
+++ b/widget/android/GeneratedJNIWrappers.cpp
@@ -72,17 +72,16 @@ jmethodID GeckoAppShell::jPerformHapticF
 jmethodID GeckoAppShell::jPumpMessageLoop = 0;
 jmethodID GeckoAppShell::jRegisterSurfaceTextureFrameListener = 0;
 jmethodID GeckoAppShell::jRemovePluginView = 0;
 jmethodID GeckoAppShell::jScanMedia = 0;
 jmethodID GeckoAppShell::jScheduleRestart = 0;
 jmethodID GeckoAppShell::jSendMessageWrapper = 0;
 jmethodID GeckoAppShell::jSetFullScreen = 0;
 jmethodID GeckoAppShell::jSetKeepScreenOn = 0;
-jmethodID GeckoAppShell::jSetSelectedLocale = 0;
 jmethodID GeckoAppShell::jSetURITitle = 0;
 jmethodID GeckoAppShell::jShowAlertNotificationWrapper = 0;
 jmethodID GeckoAppShell::jShowFilePickerAsyncWrapper = 0;
 jmethodID GeckoAppShell::jShowFilePickerForExtensionsWrapper = 0;
 jmethodID GeckoAppShell::jShowFilePickerForMimeTypeWrapper = 0;
 jmethodID GeckoAppShell::jShowInputMethodPicker = 0;
 jmethodID GeckoAppShell::jUnlockProfile = 0;
 jmethodID GeckoAppShell::jUnlockScreenOrientation = 0;
@@ -153,17 +152,16 @@ void GeckoAppShell::InitStubs(JNIEnv *jE
     jPumpMessageLoop = getStaticMethod("pumpMessageLoop", "()Z");
     jRegisterSurfaceTextureFrameListener = getStaticMethod("registerSurfaceTextureFrameListener", "(Ljava/lang/Object;I)V");
     jRemovePluginView = getStaticMethod("removePluginView", "(Landroid/view/View;Z)V");
     jScanMedia = getStaticMethod("scanMedia", "(Ljava/lang/String;Ljava/lang/String;)V");
     jScheduleRestart = getStaticMethod("scheduleRestart", "()V");
     jSendMessageWrapper = getStaticMethod("sendMessage", "(Ljava/lang/String;Ljava/lang/String;I)V");
     jSetFullScreen = getStaticMethod("setFullScreen", "(Z)V");
     jSetKeepScreenOn = getStaticMethod("setKeepScreenOn", "(Z)V");
-    jSetSelectedLocale = getStaticMethod("setSelectedLocale", "(Ljava/lang/String;)V");
     jSetURITitle = getStaticMethod("setUriTitle", "(Ljava/lang/String;Ljava/lang/String;)V");
     jShowAlertNotificationWrapper = getStaticMethod("showAlertNotification", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
     jShowFilePickerAsyncWrapper = getStaticMethod("showFilePickerAsync", "(Ljava/lang/String;J)V");
     jShowFilePickerForExtensionsWrapper = getStaticMethod("showFilePickerForExtensions", "(Ljava/lang/String;)Ljava/lang/String;");
     jShowFilePickerForMimeTypeWrapper = getStaticMethod("showFilePickerForMimeType", "(Ljava/lang/String;)Ljava/lang/String;");
     jShowInputMethodPicker = getStaticMethod("showInputMethodPicker", "()V");
     jUnlockProfile = getStaticMethod("unlockProfile", "()Z");
     jUnlockScreenOrientation = getStaticMethod("unlockScreenOrientation", "()V");
@@ -2050,45 +2048,16 @@ void GeckoAppShell::SetKeepScreenOn(bool
         env->ExceptionClear();
         env->PopLocalFrame(NULL);
         return;
     }
 
     env->PopLocalFrame(NULL);
 }
 
-void GeckoAppShell::SetSelectedLocale(const nsAString& a0) {
-    JNIEnv *env = AndroidBridge::GetJNIEnv();
-    if (!env) {
-        ALOG_BRIDGE("Aborted: No env - %s", __PRETTY_FUNCTION__);
-        return;
-    }
-
-    if (env->PushLocalFrame(1) != 0) {
-        ALOG_BRIDGE("Exceptional exit of: %s", __PRETTY_FUNCTION__);
-        env->ExceptionDescribe();
-        env->ExceptionClear();
-        return;
-    }
-
-    jstring j0 = AndroidBridge::NewJavaString(env, a0);
-
-    env->CallStaticVoidMethod(mGeckoAppShellClass, jSetSelectedLocale, j0);
-
-    if (env->ExceptionCheck()) {
-        ALOG_BRIDGE("Exceptional exit of: %s", __PRETTY_FUNCTION__);
-        env->ExceptionDescribe();
-        env->ExceptionClear();
-        env->PopLocalFrame(NULL);
-        return;
-    }
-
-    env->PopLocalFrame(NULL);
-}
-
 void GeckoAppShell::SetURITitle(const nsAString& a0, const nsAString& a1) {
     JNIEnv *env = AndroidBridge::GetJNIEnv();
     if (!env) {
         ALOG_BRIDGE("Aborted: No env - %s", __PRETTY_FUNCTION__);
         return;
     }
 
     if (env->PushLocalFrame(2) != 0) {

--- a/widget/android/GeneratedJNIWrappers.h
+++ b/widget/android/GeneratedJNIWrappers.h
@@ -79,17 +79,16 @@ public:
     static bool PumpMessageLoop();
     static void RegisterSurfaceTextureFrameListener(jobject a0, int32_t a1);
     static void RemovePluginView(jobject a0, bool a1);
     static void ScanMedia(const nsAString& a0, const nsAString& a1);
     static void ScheduleRestart();
     static void SendMessageWrapper(const nsAString& a0, const nsAString& a1, int32_t a2);
     static void SetFullScreen(bool a0);
     static void SetKeepScreenOn(bool a0);
-    static void SetSelectedLocale(const nsAString& a0);
     static void SetURITitle(const nsAString& a0, const nsAString& a1);
     static void ShowAlertNotificationWrapper(const nsAString& a0, const nsAString& a1, const nsAString& a2, const nsAString& a3, const nsAString& a4);
     static void ShowFilePickerAsyncWrapper(const nsAString& a0, int64_t a1);
     static jstring ShowFilePickerForExtensionsWrapper(const nsAString& a0);
     static jstring ShowFilePickerForMimeTypeWrapper(const nsAString& a0);
     static void ShowInputMethodPicker();
     static bool UnlockProfile();
     static void UnlockScreenOrientation();

--- a/widget/android/nsAppShell.cpp
+++ b/widget/android/nsAppShell.cpp
@@ -158,105 +158,58 @@ nsAppShell::~nsAppShell()
 
 void
 nsAppShell::NotifyNativeEvent()
 {
     MutexAutoLock lock(mCondLock);
     mQueueCond.Notify();
 }
 
-#define PREFNAME_MATCH_OS  "intl.locale.matchOS"
-#define PREFNAME_UA_LOCALE "general.useragent.locale"
 #define PREFNAME_COALESCE_TOUCHES "dom.event.touch.coalescing.enabled"
 static const char* kObservedPrefs[] = {
-  PREFNAME_MATCH_OS,
-  PREFNAME_UA_LOCALE,
   PREFNAME_COALESCE_TOUCHES,
   nullptr
 };
 
 nsresult
 nsAppShell::Init()
 {
 #ifdef PR_LOGGING
     if (!gWidgetLog)
         gWidgetLog = PR_NewLogModule("Widget");
 #endif
 
     nsresult rv = nsBaseAppShell::Init();
-    AndroidBridge* bridge = AndroidBridge::Bridge();
-
     nsCOMPtr<nsIObserverService> obsServ =
         mozilla::services::GetObserverService();
     if (obsServ) {
         obsServ->AddObserver(this, "xpcom-shutdown", false);
     }
 
     if (sPowerManagerService)
         sPowerManagerService->AddWakeLockListener(sWakeLockListener);
 
-    if (!bridge)
-        return rv;
-
     Preferences::AddStrongObservers(this, kObservedPrefs);
-
-    bool match;
-    rv = Preferences::GetBool(PREFNAME_MATCH_OS, &match);
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    if (match) {
-        GeckoAppShell::SetSelectedLocale(EmptyString());
-        return NS_OK;
-    }
-
-    nsAutoString locale;
-    rv = Preferences::GetLocalizedString(PREFNAME_UA_LOCALE, &locale);
-    if (NS_FAILED(rv)) {
-        rv = Preferences::GetString(PREFNAME_UA_LOCALE, &locale);
-    }
-
-    GeckoAppShell::SetSelectedLocale(locale);
     mAllowCoalescingTouches = Preferences::GetBool(PREFNAME_COALESCE_TOUCHES, true);
     return rv;
 }
 
 NS_IMETHODIMP
 nsAppShell::Observe(nsISupports* aSubject,
                     const char* aTopic,
                     const PRUnichar* aData)
 {
     if (!strcmp(aTopic, "xpcom-shutdown")) {
         // We need to ensure no observers stick around after XPCOM shuts down
         // or we'll see crashes, as the app shell outlives XPConnect.
         mObserversHash.Clear();
         return nsBaseAppShell::Observe(aSubject, aTopic, aData);
-    } else if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID) && aData && (
-                   nsDependentString(aData).Equals(
-                       NS_LITERAL_STRING(PREFNAME_UA_LOCALE)) ||
-                   nsDependentString(aData).Equals(
-                       NS_LITERAL_STRING(PREFNAME_COALESCE_TOUCHES)) ||
-                   nsDependentString(aData).Equals(
-                       NS_LITERAL_STRING(PREFNAME_MATCH_OS)))) {
-        bool match;
-        nsresult rv = Preferences::GetBool(PREFNAME_MATCH_OS, &match);
-        NS_ENSURE_SUCCESS(rv, rv);
-
-        if (match) {
-            GeckoAppShell::SetSelectedLocale(EmptyString());
-            return NS_OK;
-        }
-
-        nsAutoString locale;
-        if (NS_FAILED(Preferences::GetLocalizedString(PREFNAME_UA_LOCALE,
-                                                      &locale))) {
-            locale = Preferences::GetString(PREFNAME_UA_LOCALE);
-        }
-
-        GeckoAppShell::SetSelectedLocale(locale);
-
+    } else if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID) &&
+               aData &&
+               nsDependentString(aData).Equals(NS_LITERAL_STRING(PREFNAME_COALESCE_TOUCHES))) {
         mAllowCoalescingTouches = Preferences::GetBool(PREFNAME_COALESCE_TOUCHES, true);
         return NS_OK;
     }
     return NS_OK;
 }
 
 void
 nsAppShell::ScheduleNativeEventCallback()