This CL replaces e-mail with AccountId on user selection screen.

chrome/browser/ui/webui/options/chromeos/user_image_source.cc

Index: chrome/browser/ui/webui/options/chromeos/user_image_source.cc
diff --git a/chrome/browser/ui/webui/options/chromeos/user_image_source.cc b/chrome/browser/ui/webui/options/chromeos/user_image_source.cc
index 46572be08236c9d265a510e8e475c0b36b77b505..a2918c04d9bfb336d990d6f9974d051951f58f4f 100644
--- a/chrome/browser/ui/webui/options/chromeos/user_image_source.cc
+++ b/chrome/browser/ui/webui/options/chromeos/user_image_source.cc
@@ -26,9 +26,18 @@ namespace {
 void ParseRequest(const GURL& url,
                   std::string* email) {
   DCHECK(url.is_valid());
-  *email = net::UnescapeURLComponent(url.path().substr(1),
-                                    (net::UnescapeRule::URL_SPECIAL_CHARS |
-                                     net::UnescapeRule::SPACES));
+  const std::string user_id = net::UnescapeURLComponent(

[stevenjb, 2015/11/11 20:39:23]

s/user_id/serialized_account_id/

[Alexander Alekseev, 2015/11/12 06:53:04]

Done.

+      url.path().substr(1),
+      (net::UnescapeRule::URL_SPECIAL_CHARS | net::UnescapeRule::SPACES));
+  AccountId account_id(EmptyAccountId());
+  const bool status = AccountId::Deserialize(user_id, &account_id);
+  // TODO(alemate): DCHECK(status) - should happen after options page is
+  // migrated.
+  if (!status) {
+    LOG(WARNING) << "Failed to deserialize '" << user_id << "'";

[dzhioev (left Google), 2015/11/12 00:46:24]

I believe we shouldn't produce this warning, as long as it perfectly legal for
options page to use the old format.
We can introduce an additional query param to distinguish email requests from
account_id requests, i.e.:

  * chrome://userimage/old_format_email@example.com for email requests,
  * chrome://userimage/<serialized_account_id>?format=account_id for account_id
requests.

[Alexander Alekseev, 2015/11/12 06:53:04]

I don't think we should support other ID formats for long. So this is going to
be removed after migration.

+    account_id = AccountId::FromUserEmail(user_id);
+  }
+  *email = account_id.GetUserEmail();
 }
 
 }  // namespace