[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>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/chromeos/arc/arc_auth_context.h"
 #include "chrome/browser/chromeos/arc/arc_optin_uma.h"
 #include "chrome/browser/chromeos/arc/auth/arc_auth_code_fetcher.h"
 #include "google_apis/gaia/oauth2_token_service.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
 class Profile;
 
 namespace net {
 class URLFetcher;
 class URLRequestContextGetter;
 }  // namespace net
 
 namespace arc {
 
+// Exposed for testing.
+extern const char kAuthTokenExchangeEndPoint[];
+
 // 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;
 
   // ArcAuthCodeFetcher:
@@ skipping 27 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_