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

chrome/browser/chromeos/login/user_manager_impl.cc

Index: chrome/browser/chromeos/login/user_manager_impl.cc
diff --git a/chrome/browser/chromeos/login/user_manager_impl.cc b/chrome/browser/chromeos/login/user_manager_impl.cc
index 2cdd827c95c3318099e7bf118acb85cbf151108d..a51279348b7f0973e287f982e6c7ff7454084bdc 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.cc
+++ b/chrome/browser/chromeos/login/user_manager_impl.cc
@@ -376,11 +376,18 @@ void UserManagerImpl::EphemeralUserLoggedIn(const std::string& email) {
 
 void UserManagerImpl::InitializeWallpaper() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  if (WizardController::IsZeroDelayEnabled())
+    return;
+
+  bool disable_new_oobe = CommandLine::ForCurrentProcess()->
+      HasSwitch(switches::kDisableNewOobe);
+  bool disable_boot_animation = CommandLine::ForCurrentProcess()->
+      HasSwitch(switches::kDisableBootAnimation);
+
   if (!IsUserLoggedIn()) {
-    if (!CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kDisableNewOobe)) {
-      if (!WizardController::IsDeviceRegistered() &&
-          !WizardController::IsZeroDelayEnabled()) {
+    if (!disable_new_oobe) {
+      if (!WizardController::IsDeviceRegistered()) {
         // TODO(nkostylev): Add switch to disable wallpaper transition on OOBE.
         // Should be used on test images so that they are not slowed down.
         ash::Shell::GetInstance()->desktop_background_controller()->
@@ -392,8 +399,18 @@ void UserManagerImpl::InitializeWallpaper() {
         DCHECK(result) << "Unable to fetch setting "
                        << kAccountsPrefShowUserNamesOnSignIn;
         if (!show_users) {
+          // Boot into sign in form, preload default wallpaper.
           ash::Shell::GetInstance()->desktop_background_controller()->
-              SetDefaultWallpaper(ash::GetSolidColorIndex());
+              SetDefaultWallpaper(kDefaultOOBEWallpaperIndex);
+        } else if (!disable_boot_animation) {
+          // Normal boot, load user wallpaper.
+          const chromeos::UserList& users = GetUsers();
+          if (!users.empty()) {
+            UserSelected(users[0]->email());
+          } else {
+            ash::Shell::GetInstance()->desktop_background_controller()->
+                SetDefaultWallpaper(kDefaultOOBEWallpaperIndex);
+          }
         }
       }
     }