[ARC] Add browser test of ArcAuthService

chrome/browser/chromeos/arc/auth/arc_background_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_AUTH_ARC_BACKGROUND_AUTH_CODE_FETCHER_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_AUTH_ARC_BACKGROUND_AUTH_CODE_FETCHER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 17 matching lines @@
 
 // The instance is not reusable, so for each Fetch(), the instance must be
 // re-created. Deleting the instance cancels inflight operation.
 class ArcBackgroundAuthCodeFetcher : public ArcAuthCodeFetcher,
                                      public OAuth2TokenService::Consumer,
                                      public net::URLFetcherDelegate {
  public:
   ArcBackgroundAuthCodeFetcher(Profile* profile, ArcAuthContext* context);
   ~ArcBackgroundAuthCodeFetcher() override;
 
+  // Exposed for testing.
+  static std::string GetTokenExchangeEndpoint();

[Luis Héctor Chávez, 2017/05/11 16:57:54]

nit: add "ForTesting" suffix.

[blundell, 2017/05/12 09:09:32]

Done.

+
   // ArcAuthCodeFetcher:
   void Fetch(const FetchCallback& callback) override;
 
  private:
   void ResetFetchers();
   void OnPrepared(net::URLRequestContextGetter* request_context_getter);
 
   // OAuth2TokenService::Consumer:
   void OnGetTokenSuccess(const OAuth2TokenService::Request* request,
                          const std::string& access_token,
@@ skipping 18 matching lines @@
   std::unique_ptr<net::URLFetcher> auth_code_fetcher_;
 
   base::WeakPtrFactory<ArcBackgroundAuthCodeFetcher> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcBackgroundAuthCodeFetcher);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_AUTH_ARC_BACKGROUND_AUTH_CODE_FETCHER_H_