Move device admin max screen off timeout to internal interface.

The setting was previously exposed in IPowerManager but it
doesn't need to be there.

Bug: 17656076
Change-Id: If3ed0cbe89f67c60aa00376be0c54b1bd9656144

core/java/android/os/IPowerManager.aidl

@@ -49,7 +49,6 @@ interface IPowerManager
     void crash(String message);
 
     void setStayOnSetting(int val);
-    void setMaximumScreenOffTimeoutFromDeviceAdmin(int timeMs);
     void boostScreenBrightness(long time);
 
     // temporarily overrides the screen brightness settings to allow the user to

core/java/android/os/PowerManagerInternal.java

@@ -55,6 +55,13 @@ public abstract class PowerManagerInternal {
      */
     public abstract void setUserActivityTimeoutOverrideFromWindowManager(long timeoutMillis);
 
+    /**
+     * Used by device administration to set the maximum screen off timeout.
+     *
+     * This method must only be called by the device administration policy manager.
+     */
+    public abstract void setMaximumScreenOffTimeoutFromDeviceAdmin(int timeMs);
+
     /**
      * Used by the dream manager to override certain properties while dozing.
      *