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 82 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 the all display's oientation. The value should be one of 0=(normal)

[Daniel Erat, 2013/01/30 21:04:27]

nit: fixing some typos and grammar:

// Overrides all displays' orientation.  The value should be
// one of 0 (normal), 1 (90 degrees clockwise), 2 (180
// degrees), or 3 (270 degrees clockwise / 90 degrees
// counter-clockwise).

but it'd be better to add an enum somewhere and use the values from that
instead, e.g.

enum DisplayOrientation {
  DISPLAY_ORIENTATION_NORMAL,
  DISPLAY_ORIENTATION_90_DEGREES_CW,
  DISPLAY_ORIENTATION_180_DEGREES,
  DISPLAY_ORIENTATION_90_DEGREES_CCW,
};

or something similar.  or maybe having constants with descriptive strings would
be even better.

[oshima, 2013/01/30 23:45:53]

Updated the comment. I agree that it should be enum, but i want to do it when
I work on real implementation (it will be in ui/gfx/display.h). For now, i want
to keep it just int as all we want is to be able to pass this integer
value from command line to X/driver. (and enum wont be used anywhere now)

+// 1=(90 degree clock wise), 2=(180 degree) or 3=(270 degree).
+const char kAshOverrideDisplayOrientation[] =
+    "ash-override-display-orientation";
+
 }  // namespace switches
 }  // namespace ash