Set scale/orientation property to aura root window

ash/ash_switches.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/ash_switches.h"
 
 namespace ash {
 namespace switches {
 
 // Enables an animated transition from the boot splash screen (Chrome logo on a
@@ skipping 79 matching lines @@
 
 // (Most) Chrome OS hardware reports ACPI power button releases correctly.
 // Standard hardware reports releases immediately after presses.  If set, we
 // lock the screen or shutdown the system immediately in response to a press
 // instead of displaying an interactive animation.
 const char kAuraLegacyPowerButton[] = "aura-legacy-power-button";
 
 // Avoid drawing drop shadows under windows.
 const char kAuraNoShadows[] = "aura-no-shadows";
 
+// Overrides all displays' orientation. The value should be one of 0
+// (normal), 1 (90 degrees clockwise), 2 (180 degrees) or 3 (270
+// degrees clockwise).
+const char kAshOverrideDisplayOrientation[] =
+    "ash-override-display-orientation";
+
 }  // namespace switches
 }  // namespace ash