Disable system alert window permissions on low ram devices

Bug: 63697002
Bug: 117832554
Test: adb am start-activity -a
android.settings.action.MANAGE_OVERLAY_PERMISSION
Change-Id: I44c64001cd07fd4934cdc55f455384cebd5c9cfb

tests/robotests/src/com/android/settings/testutils/shadow/ShadowUtils.java

@@ -38,6 +38,7 @@ public class ShadowUtils {
     private static boolean sIsDemoUser;
     private static ComponentName sDeviceOwnerComponentName;
     private static Map<String, String> sAppNameMap;
+    private static boolean sIsSystemAlertWindowEnabled;
 
     @Implementation
     protected static int enforceSameOwner(Context context, int userId) {
@@ -113,4 +114,13 @@ public class ShadowUtils {
         }
         sAppNameMap.put(packageName, appLabel);
     }
+
+    @Implementation
+    protected static boolean isSystemAlertWindowEnabled(Context context) {
+        return sIsSystemAlertWindowEnabled;
+    }
+
+    public static void setIsSystemAlertWindowEnabled(boolean enabled) {
+        sIsSystemAlertWindowEnabled = enabled;
+    }
 }