Add system API to watch for permission changes

Change-Id: I1ce450a59fb326c14848f46732d877dea33f33c7
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 709de9e..0911d42 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -1979,6 +1979,10 @@
     <permission android:name="android.permission.GRANT_REVOKE_PERMISSIONS"
         android:protectionLevel="signature" />
 
+    <!-- @hide Allows an application to observe permission changes. -->
+    <permission android:name="android.permission.OBSERVE_GRANT_REVOKE_PERMISSIONS"
+        android:protectionLevel="signatureOrSystem" />
+
     <!-- Allows an application to use SurfaceFlinger's low level features.
     <p>Not for use by third-party applications. -->
     <permission android:name="android.permission.ACCESS_SURFACE_FLINGER"