Asynchronously load wallpapers when user pod is selected.

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 a004cc9adf88ea1ca21497bc0b12c834f340c121..4dbef649a711a3b611fe2ffbf0b2b8cf4ef329a7 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.cc
+++ b/chrome/browser/chromeos/login/user_manager_impl.cc
@@ -383,6 +383,7 @@ void UserManagerImpl::UserLoggedIn(const std::string& email) {
 
   if (is_current_user_new_) {
     SetInitialUserImage(email);
+    SetInitialUserWallpaper(email);
   } else {
     // Download profile image if it's user image and see if it has changed.
     int image_index = logged_in_user_->image_index();
@@ -421,6 +422,7 @@ void UserManagerImpl::DemoUserLoggedIn() {
   is_current_user_ephemeral_ = true;
   logged_in_user_ = new User(kDemoUser, false);
   SetInitialUserImage(kDemoUser);
+  SetInitialUserWallpaper(kDemoUser);
   NotifyOnLogin();
 }
 
@@ -429,6 +431,7 @@ void UserManagerImpl::GuestUserLoggedIn() {
   // Guest user always uses the same wallpaper.
   current_user_wallpaper_index_ = ash::GetGuestWallpaperIndex();
   logged_in_user_ = new User(kGuestUser, true);
+  SetInitialUserWallpaper(kGuestUser);
   NotifyOnLogin();
 }
 
@@ -437,6 +440,7 @@ void UserManagerImpl::EphemeralUserLoggedIn(const std::string& email) {
   is_current_user_ephemeral_ = true;
   logged_in_user_ = CreateUser(email);
   SetInitialUserImage(email);
+  SetInitialUserWallpaper(email);
   NotifyOnLogin();
 }
 
@@ -446,6 +450,14 @@ void UserManagerImpl::StubUserLoggedIn() {
   logged_in_user_ = new User(kStubUser, false);
   logged_in_user_->SetImage(GetDefaultImage(kStubDefaultImageIndex),
                             kStubDefaultImageIndex);
+  SetInitialUserWallpaper(kStubUser);
+}
+
+void UserManagerImpl::UserSelected(const std::string& email) {
+  if (IsKnownUser(email)) {
+    ash::Shell::GetInstance()->desktop_background_controller()->
+        SetDefaultWallpaper(FindUserWallpaperIndex(email));
+  }
 }
 
 void UserManagerImpl::RemoveUser(const std::string& email,
@@ -882,6 +894,20 @@ const User* UserManagerImpl::FindUserInList(const std::string& email) const {
   return NULL;
 }
 
+int UserManagerImpl::FindUserWallpaperIndex(const std::string& email) {
+  PrefService* local_state = g_browser_process->local_state();
+  const DictionaryValue* user_wallpapers =
+      local_state->GetDictionary(UserManager::kUserWallpapers);
+  int index;
+  if (!user_wallpapers->GetIntegerWithoutPathExpansion(email, &index))
+    index = current_user_wallpaper_index_;
+  if (index < 0 || index >= ash::GetWallpaperCount()) {
+      index = ash::GetDefaultWallpaperIndex();
+      SaveUserWallpaperIndex(index);
+  }
+  return index;
+}
+
 void UserManagerImpl::NotifyOnLogin() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   content::NotificationService::current()->Notify(
@@ -930,6 +956,16 @@ void UserManagerImpl::SetInitialUserImage(const std::string& username) {
   SaveUserDefaultImageIndex(username, image_id);
 }
 
+void UserManagerImpl::SetInitialUserWallpaper(const std::string& username) {
+  if (username == kGuestUser)
+    current_user_wallpaper_index_ = ash::GetGuestWallpaperIndex();
+  else
+    current_user_wallpaper_index_ = ash::GetDefaultWallpaperIndex();

[Nikita (slow), 2012/05/02 09:22:23]

Ideally we might start preloading some random wallpaper when "Add user" flow is
started from sign in screen, right?

In fact it is not that bad as user is shown an avatar selection so wallpaper
load would happen in the background during that time.

[bshe, 2012/05/03 01:02:00]

I agree, ideally we should start loading wallpaper when "add user" flow started
and revert to last used wallpaper if user hit "cancel". Add a todo here.

+   SaveUserWallpaperIndex(current_user_wallpaper_index_);
+   ash::Shell::GetInstance()->desktop_background_controller()->
+       SetDefaultWallpaper(current_user_wallpaper_index_);
+}
+
 int UserManagerImpl::GetUserWallpaperIndex() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
@@ -944,19 +980,7 @@ int UserManagerImpl::GetUserWallpaperIndex() {
   const chromeos::User& user = GetLoggedInUser();
   std::string username = user.email();
   DCHECK(!username.empty());
-
-  PrefService* local_state = g_browser_process->local_state();
-  const DictionaryValue* user_wallpapers =
-      local_state->GetDictionary(UserManager::kUserWallpapers);
-  int index;
-  if (!user_wallpapers->GetIntegerWithoutPathExpansion(username, &index))
-    index = current_user_wallpaper_index_;
-
-  if (index < 0 || index >= ash::GetWallpaperCount()) {
-    index = ash::GetDefaultWallpaperIndex();
-    SaveUserWallpaperIndex(index);
-  }
-  return index;
+  return FindUserWallpaperIndex(username);
 }
 
 void UserManagerImpl::SaveUserWallpaperIndex(int wallpaper_index) {