Delay wallpaper load by 2 * average wallpaper load time.

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
index 497945c120b28e38a598f592d65da024faab6795..1018c516a937ac0fbe4709d796c57c5ada120058 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -391,6 +391,7 @@ SigninScreenHandler::SigninScreenHandler(
       network_state_informer_(network_state_informer),
       test_expects_complete_login_(false),
       weak_factory_(this),
+      weak_factory_as_observer_(this),
       webui_visible_(false),
       preferences_changed_delayed_(false),
       error_screen_actor_(error_screen_actor),
@@ -554,8 +555,11 @@ void SigninScreenHandler::ShowRetailModeLoginSpinner() {
 
 void SigninScreenHandler::SetDelegate(SigninScreenHandlerDelegate* delegate) {
   delegate_ = delegate;
-  if (delegate_)
+  if (delegate_) {
     delegate_->SetWebUIHandler(this);
+    WallpaperManager::Get()->AddObserver(
+        weak_factory_as_observer_.GetWeakPtr());
+  }
 }
 
 void SigninScreenHandler::SetNativeWindowDelegate(
@@ -1285,6 +1289,11 @@ void SigninScreenHandler::HandleLoadWallpaper(const std::string& email) {
     delegate_->LoadWallpaper(email);
 }
 
+void SigninScreenHandler::OnWallpaperAnimationFinished(
+    const std::string& email) {
+  CallJS("login.AccountPickerScreen.onWallpaperLoaded", email);
+}
+
 void SigninScreenHandler::HandleRebootSystem() {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->RequestRestart();
 }