arc: Prepare ArcAuthEndpoint flag for finch experiment.

chrome/browser/chromeos/arc/arc_auth_code_fetcher.h

 // Copyright 2016 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_ARC_ARC_AUTH_CODE_FETCHER_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_CODE_FETCHER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 11 matching lines @@
 class URLRequestContextGetter;
 }
 
 namespace arc {
 
 // The instance is not reusable, so for each Fetch(), the instance must be
 // re-created. Deleting the instance cancels inflight operation.
 class ArcAuthCodeFetcher : public OAuth2TokenService::Consumer,
                            public net::URLFetcherDelegate {
  public:
-  ArcAuthCodeFetcher(Profile* profile,
-                     ArcAuthContext* context,
-                     const std::string& auth_endpoint);
+  ArcAuthCodeFetcher(Profile* profile, ArcAuthContext* context);
   ~ArcAuthCodeFetcher() override;
 
   // Starts to fetch the token. On success fetched |auth_token| is passed.
   // On error, auth_token is empty.
   using FetchCallback = base::Callback<void(const std::string& auth_token)>;
   void Fetch(const FetchCallback& callback);
 
   // OAuth2TokenService::Consumer:
   void OnGetTokenSuccess(const OAuth2TokenService::Request* request,
                          const std::string& access_token,
                          const base::Time& expiration_time) override;
   void OnGetTokenFailure(const OAuth2TokenService::Request* request,
                          const GoogleServiceAuthError& error) override;
 
   // net::URLFetcherDelegate:
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
  private:
   void ResetFetchers();
   void OnPrepared(net::URLRequestContextGetter* request_context_getter);
 
   // Unowned pointers.
   Profile* const profile_;
   ArcAuthContext* const context_;
   net::URLRequestContextGetter* request_context_getter_ = nullptr;
 
-  // URL to request auth code.
-  const std::string auth_endpoint_;
-
   FetchCallback callback_;
 
   std::unique_ptr<OAuth2TokenService::Request> login_token_request_;
   std::unique_ptr<net::URLFetcher> auth_code_fetcher_;
 
   base::WeakPtrFactory<ArcAuthCodeFetcher> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcAuthCodeFetcher);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_CODE_FETCHER_H_