Canonicalize user ID passed via chromeos::switches::kLoginUser

chrome/browser/chromeos/login/helper.h

Index: chrome/browser/chromeos/login/helper.h
diff --git a/chrome/browser/chromeos/login/helper.h b/chrome/browser/chromeos/login/helper.h
index b481c5fa2ac4cd51f95305337998a4bf973ee75b..c813eb2ebc9521d7e0023fa6e2981818cb9c4a89 100644
--- a/chrome/browser/chromeos/login/helper.h
+++ b/chrome/browser/chromeos/login/helper.h
@@ -7,6 +7,8 @@
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_HELPER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_HELPER_H_
 
+#include <string>
+
 #include "base/compiler_specific.h"
 #include "base/strings/string16.h"
 #include "third_party/skia/include/core/SkColor.h"
@@ -37,6 +39,11 @@ namespace login {
 // displayed under all possible DPI values.
 const int kMaxUserImageSize = 512;
 
+// Canonicalizes a GAIA user ID, accounting for the legacy guest mode user ID
+// which does trips up gaia::CanonicalizeEmail() because it does not contain an
+// @ symbol.
+std::string CanonicalizeUserID(const std::string& user_id);
+
 // A helper class for easily mocking out Network*Handler calls for tests.
 class NetworkStateHelper {
  public: