Fix broken window flag

It got lost in reverts and un-reverts.

Test: open settings
Change-Id: I243209a8d2b63ef57829abfdd3f14c00dfdf25ea
Fixes: 65495538

core/java/com/android/internal/policy/PhoneWindow.java

@@ -2456,6 +2456,10 @@ public class PhoneWindow extends Window implements MenuBuilder.Callback {
             decor.setSystemUiVisibility(
                     decor.getSystemUiVisibility() | View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
         }
+        if (a.getBoolean(R.styleable.Window_windowLightNavigationBar, false)) {
+            decor.setSystemUiVisibility(
+                    decor.getSystemUiVisibility() | View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR);
+        }
 
         if (mAlwaysReadCloseOnTouchAttr || getContext().getApplicationInfo().targetSdkVersion
                 >= android.os.Build.VERSION_CODES.HONEYCOMB) {