Pass Device ID in the oauth2/token request. Keep Device ID in local state on Chrome OS.

chrome/browser/signin/chrome_signin_client.h

 // 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.
 
 #ifndef CHROME_BROWSER_SIGNIN_CHROME_SIGNIN_CLIENT_H_
 #define CHROME_BROWSER_SIGNIN_CHROME_SIGNIN_CLIENT_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "components/signin/core/browser/signin_client.h"
@@ skipping 15 matching lines @@
  public:
   explicit ChromeSigninClient(
       Profile* profile, SigninErrorController* signin_error_controller);
   ~ChromeSigninClient() override;
   void Shutdown() override;
 
   // Utility methods.
   static bool ProfileAllowsSigninCookies(Profile* profile);
   static bool SettingsAllowSigninCookies(CookieSettings* cookie_settings);
 
+  // If |for_ephemeral| is true, special kind of device ID for ephemeral users
+  // is generated.
+  static std::string GenerateSigninScopedDeviceID(bool for_ephemeral);
+
   // SigninClient implementation.
   PrefService* GetPrefs() override;
   scoped_refptr<TokenWebData> GetDatabase() override;
   bool CanRevokeCredentials() override;
   std::string GetSigninScopedDeviceId() override;
   void OnSignedOut() override;
   net::URLRequestContextGetter* GetURLRequestContext() override;
   bool ShouldMergeSigninCredentialsIntoCookieJar() override;
   bool IsFirstRun() const override;
   base::Time GetInstallDate() override;
@@ skipping 36 matching lines @@
 
   SigninErrorController* signin_error_controller_;
 #if !defined(OS_CHROMEOS)
   std::list<base::Closure> delayed_callbacks_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ChromeSigninClient);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_CHROME_SIGNIN_CLIENT_H_