ash: Clean up system background layer.

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 {
 
 // Variation of boot animation that uses Tween::EASE_OUT_2.
 const char kAshBootAnimationFunction2[] = "ash-boot-animation-function2";
 
 // Variation of boot animation that uses Tween::EASE_OUT_3.
 const char kAshBootAnimationFunction3[] = "ash-boot-animation-function3";
 
 // Constrains the pointer movement within a root window on desktop.
 const char kAshConstrainPointerToRoot[] = "ash-constrain-pointer-to-root";
 
+// Copies the host window's content to the system background layer at startup.
+// Can make boot slightly slower, but also hides an even-longer awkward period
+// where we display a white background if the login wallpaper takes a long time
+// to load.
+const char kAshCopyHostBackgroundAtBoot[] = "ash-copy-host-background-at-boot";
+
 // Enable keyboard shortcuts useful for debugging.
 const char kAshDebugShortcuts[] = "ash-debug-shortcuts";
 
 // Disables boot animation v2, go back to v1.
 const char kAshDisableBootAnimation2[] = "ash-disable-boot-animation2";
 
 // Disables panel fitting (used for mirror mode).
 const char kAshDisablePanelFitting[] = "ash-disable-panel-fitting";
 
 // Enable advanced gestures (e.g. for window management).
@@ skipping 30 matching lines @@
 // 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";
 
 }  // namespace switches
 }  // namespace ash