We should use UserID object to identify users instead of username.

chrome/browser/ui/app_list/speech_auth_helper.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/ui/app_list/speech_auth_helper.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/time/clock.h"
@@ skipping 65 matching lines @@
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   auth_token_ = "";
   auth_token_request_.reset();
 
   // Try again later.
   // TODO(amistry): Implement backoff.
   ScheduleTokenFetch(
       base::TimeDelta::FromSeconds(kMinTokenRefreshDelaySeconds));
 }
 
-void SpeechAuthHelper::OnRefreshTokenAvailable(const std::string& account_id) {
+void SpeechAuthHelper::OnRefreshTokenAvailable(const std::string& user_id) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  if (authenticated_account_id_ == account_id)
+  if (authenticated_account_id_ == user_id)
     FetchAuthToken();
 }
 
 void SpeechAuthHelper::ScheduleTokenFetch(const base::TimeDelta& fetch_delay) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   content::BrowserThread::PostDelayedTask(
       content::BrowserThread::UI,
       FROM_HERE,
       base::Bind(&SpeechAuthHelper::FetchAuthToken,
                  weak_factory_.GetWeakPtr()),
@@ skipping 17 matching lines @@
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   return auth_token_;
 }
 
 std::string SpeechAuthHelper::GetScope() const {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   return kAuthScope;
 }
 
 }  // namespace app_list