Add TabletModeChangedListener for SystemUI.

Bug: 23256614
Change-Id: I6e5d636c24a84846cfad84da800911a469689dda
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 58f2d47..446b67f 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -2014,6 +2014,12 @@
     <permission android:name="android.permission.SET_KEYBOARD_LAYOUT"
         android:protectionLevel="signature" />
 
+    <!-- Allows an application to monitor changes in tablet mode.
+         <p>Not for use by third-party applications.
+         @hide -->
+    <permission android:name="android.permission.TABLET_MODE_LISTENER"
+        android:protectionLevel="signature" />
+
     <!-- Allows an application to request installing packages. Apps
          targeting APIs greater than 22 must hold this permission in
          order to use {@link android.content.Intent#ACTION_INSTALL_PACKAGE}.