This CL replaces e-mail with AccountId in easy signin code.

chrome/browser/chromeos/login/easy_unlock/easy_unlock_challenge_wrapper.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_EASY_UNLOCK_EASY_UNLOCK_CHALLENGE_WRAPPER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_EASY_UNLOCK_EASY_UNLOCK_CHALLENGE_WRAPPER_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "components/signin/core/account_id/account_id.h"
 
 class EasyUnlockTpmKeyManager;
 
 namespace chromeos {
 
 // Wraps a user challenge in a SecureMessage that can be verified by the remote
 // device, containing the signature by the TPM of some unique data from the
 // secure channel between the two devices.
 class EasyUnlockChallengeWrapper {
  public:
   // Creates the instance:
   // |challenge|: The raw challenge to wrap.
   // |channel_binding_data|: Data unique to the current secure channel such that
   //                         we can bind with a TPM signature.
-  // |user_id|: The id of the user who owns both devices.
+  // |account_id|: The id of the user who owns both devices.
   // |key_manager|: Responsible for signing some piece of data with the TPM.
   //                Not owned and should outlive this instance.
   EasyUnlockChallengeWrapper(const std::string& challenge,
                              const std::string& channel_binding_data,
-                             const std::string& user_id,
+                             const AccountId& account_id,
                              EasyUnlockTpmKeyManager* key_manager);
   virtual ~EasyUnlockChallengeWrapper();
 
   // Wraps the challenge and invokes |callback| with the |wrapped_challenge|
   // that will be send directly to the remote device.
   typedef base::Callback<void(const std::string& wrapped_challenge)>
       WrappedChallengeCallback;
   void WrapChallenge(const WrappedChallengeCallback& callback);
 
  protected:
   // Signs |data_to_sign| with the TPM. |callback| will be invoked upon
   // completion. Exposed for testing.
   virtual void SignUsingTpmKey(
       const std::string& data_to_sign,
       const base::Callback<void(const std::string&)>& callback);
 
  private:
   // Called when the channel binding data is signed by the TPM and completes the
   // wrapping.
   void OnChannelBindingDataSigned(const std::string& signature_metadata,
                                   const std::string& signature);
 
   // The raw challenge for the remote device.
   const std::string challenge_;
 
   // Data specific to the current secure channel to be signed by the TPM.
   const std::string channel_binding_data_;
 
   // The id of the user who owns both devices.
-  const std::string user_id_;
+  const AccountId account_id_;
 
   // Responsible for signing data with the TPM. Not owned.
   EasyUnlockTpmKeyManager* key_manager_;
 
   // Called when wrapping completes.
   WrappedChallengeCallback callback_;
 
   base::WeakPtrFactory<EasyUnlockChallengeWrapper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EasyUnlockChallengeWrapper);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_EASY_UNLOCK_EASY_UNLOCK_CHALLENGE_WRAPPER_H_