[cros] Choose initial user avatar from new stock images only.

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 6cb84438c1379afd1d6ac41e388952f60a94aa15..6f2251fa7bcf316ceeb5d02b8bf58c01166f57c8 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.cc
+++ b/chrome/browser/chromeos/login/user_manager_impl.cc
@@ -904,7 +904,8 @@ void UserManagerImpl::NotifyOnLogin() {
 
 void UserManagerImpl::SetInitialUserImage(const std::string& username) {
   // Choose a random default image.
-  int image_id = base::RandInt(0, kDefaultImagesCount - 1);
+  int image_id =
+      base::RandInt(kFirstDefaultImageIndex, kDefaultImagesCount - 1);
   SaveUserDefaultImageIndex(username, image_id);
 }