Clear locales without changing layout direction.

Calling Configuration.setLocales with emtpy LocaleList may change the
layout direction to LTR. To clear the locales in Configuration without
layout direction change, introduce hidden API to Configuration.

Bug: 28695661
Change-Id: I47c339dffb83099bd329ddb60237dab27b05f593

core/java/android/content/res/Configuration.java

@@ -1484,6 +1484,16 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         setLocales(loc == null ? LocaleList.getEmptyLocaleList() : new LocaleList(loc));
     }
 
+    /**
+     * @hide
+     *
+     * Clears the locale without changing layout direction.
+     */
+    public void clearLocales() {
+        mLocaleList = LocaleList.getEmptyLocaleList();
+        locale = null;
+    }
+
     /**
      * Return the layout direction. Will be either {@link View#LAYOUT_DIRECTION_LTR} or
      * {@link View#LAYOUT_DIRECTION_RTL}.

core/java/android/provider/Settings.java

@@ -2241,7 +2241,7 @@ public final class Settings {
         public static void clearConfiguration(Configuration inoutConfig) {
             inoutConfig.fontScale = 0;
             if (!inoutConfig.userSetLocale && !inoutConfig.getLocales().isEmpty()) {
-                inoutConfig.setLocales(LocaleList.getEmptyLocaleList());
+                inoutConfig.clearLocales();
             }
         }