Make sure GetAuthenticatedAccountId() returns a canonicalized id.

chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc

 // Copyright 2013 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/chromeos/extensions/file_manager/private_api_drive.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/drive/drive_integration_service.h"
 #include "chrome/browser/chromeos/extensions/file_manager/private_api_util.h"
@@ skipping 985 matching lines @@
   }
 
   download_url_ =
       google_apis::DriveApiUrlGenerator::kBaseDownloadUrlForProduction +
       entry->resource_id();
 
   ProfileOAuth2TokenService* oauth2_token_service =
       ProfileOAuth2TokenServiceFactory::GetForProfile(GetProfile());
   SigninManagerBase* signin_manager =
       SigninManagerFactory::GetForProfile(GetProfile());
-  const std::string& account_id = signin_manager->GetAuthenticatedAccountId();
+  std::string account_id = signin_manager->GetAuthenticatedAccountId();
   std::vector<std::string> scopes;
   scopes.push_back("https://www.googleapis.com/auth/drive.readonly");
 
   auth_service_.reset(
       new google_apis::AuthService(oauth2_token_service,
                                    account_id,
                                    GetProfile()->GetRequestContext(),
                                    scopes));
   auth_service_->StartAuthentication(base::Bind(
       &FileManagerPrivateGetDownloadUrlFunction::OnTokenFetched, this));
 }
 
 void FileManagerPrivateGetDownloadUrlFunction::OnTokenFetched(
     google_apis::GDataErrorCode code,
     const std::string& access_token) {
   if (code != google_apis::HTTP_SUCCESS) {
     SetError("Not able to fetch the token.");
     SetResult(new base::StringValue(""));  // Intentionally returns a blank.
     SendResponse(false);
     return;
   }
 
   const std::string url = download_url_ + "?access_token=" + access_token;
   SetResult(new base::StringValue(url));
 
   SendResponse(true);
 }
 
 }  // namespace extensions