Make adb shell am display-size persistent.

Change-Id: If3d5d18729f4e89eb7e689994deadd996fd487e9
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 6deb5a0..fbdc0ba 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -2545,6 +2545,13 @@
             "lock_screen_owner_info_enabled";
 
         /**
+         * The saved value for WindowManagerService.setForcedDisplaySize().
+         * Two integers separated by a comma.  If unset, then use the real display size.
+         * @hide
+         */
+        public static final String DISPLAY_SIZE_FORCED = "display_size_forced";
+
+        /**
          * Whether assisted GPS should be enabled or not.
          * @hide
          */