Enable wallpaper boot animation for boot into sign in too. Add flag to disable it.

chrome/common/chrome_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 "chrome/common/chrome_switches.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 
 namespace switches {
@@ skipping 1322 matching lines @@
 // Uses WinHTTP to fetch and evaluate PAC scripts. Otherwise the default is to
 // use Chromium's network stack to fetch, and V8 to evaluate.
 const char kWinHttpProxyResolver[]          = "winhttp-proxy-resolver";
 
 #if defined(OS_ANDROID)
 // Use the tablet specific UI components when available.
 const char kTabletUI[]                      = "tablet-ui";
 #endif
 
 #if defined(OS_CHROMEOS)
+// Disables wallpaper boot animation (except of OOBE case).
+const char kDisableBootAnimation[]          = "disable-boot-animation";
+
 // Disables gdata content provider.
 const char kDisableGData[]                  = "disable-gdata";
 
 // Disables new WebRTC implementation of user image picker.
 const char kDisableHtml5Camera[]            = "disable-html5-camera";
 
 // Disables new OOBE/sign in design.
 const char kDisableNewOobe[]                = "disable-new-oobe";
 
 // Enables touchpad three-finger-click as middle button.
@@ skipping 171 matching lines @@
 
 // -----------------------------------------------------------------------------
 // DO NOT ADD YOUR CRAP TO THE BOTTOM OF THIS FILE.
 //
 // You were going to just dump your switches here, weren't you? Instead, please
 // put them in alphabetical order above, or in order inside the appropriate
 // ifdef at the bottom. The order should match the header.
 // -----------------------------------------------------------------------------
 
 }  // namespace switches