[cros] Encode user images when set from WebUI (regression fix).

chrome/browser/chromeos/login/user.cc

Index: chrome/browser/chromeos/login/user.cc
diff --git a/chrome/browser/chromeos/login/user.cc b/chrome/browser/chromeos/login/user.cc
index 835b0bd0693debacec38b64899d02a3e88d79214..da797c362de6f8e9208458fed64b6148c631495d 100644
--- a/chrome/browser/chromeos/login/user.cc
+++ b/chrome/browser/chromeos/login/user.cc
@@ -47,6 +47,7 @@ void User::SetImage(const UserImage& user_image, int image_index) {
   user_image_ = user_image;
   image_index_ = image_index;
   image_is_stub_ = false;
+  DCHECK(HasDefaultImage() || user_image.has_raw_image());
 }
 
 void User::SetImageURL(const GURL& image_url) {
@@ -70,6 +71,10 @@ std::string User::GetAccountName(bool use_display_email) const {
     return GetUserName(email_);
 }
 
+bool User::HasDefaultImage() const {
+  return image_index_ >= 0 && image_index_ < kDefaultImagesCount;
+}
+
 string16 User::GetDisplayName() const {
   // Fallback to the email account name in case display name haven't been set.
   return display_name_.empty() ?