Refactor CryptAuth component to be more testable.

components/proximity_auth/cryptauth/cryptauth_client_factory.cc

-// Copyright 2015 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 "components/proximity_auth/cryptauth/cryptauth_client_factory.h"
-
-#include "components/proximity_auth/cryptauth/cryptauth_account_token_fetcher.h"
-
-namespace proximity_auth {
-
-CryptAuthClientFactory::CryptAuthClientFactory(
-    OAuth2TokenService* token_service,
-    const std::string& account_id,
-    scoped_refptr<net::URLRequestContextGetter> url_request_context,
-    const cryptauth::DeviceClassifier& device_classifier)
-    : token_service_(token_service),
-      account_id_(account_id),
-      url_request_context_(url_request_context),
-      device_classifier_(device_classifier) {
-}
-
-CryptAuthClientFactory::~CryptAuthClientFactory() {
-}
-
-scoped_ptr<CryptAuthClient> CryptAuthClientFactory::CreateInstance() {
-  scoped_ptr<CryptAuthAccessTokenFetcher> access_token_fetcher(
-      new CryptAuthAccountTokenFetcher(token_service_, account_id_));
-  return make_scoped_ptr(new CryptAuthClient(
-      access_token_fetcher.Pass(), url_request_context_, device_classifier_));
-}
-
-}  // namespace proximity_auth