[chromecast] Merge ChromecastBrowserTestHelper into ChromecastBrowserTest

chromecast/browser/test/chromecast_browser_test_helper.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 CHROMECAST_BROWSER_TEST_CHROMECAST_BROWSER_TEST_HELPER_H_
-#define CHROMECAST_BROWSER_TEST_CHROMECAST_BROWSER_TEST_HELPER_H_
-
-#include <memory>
-
-class GURL;
-
-namespace content {
-class WebContents;
-}
-
-namespace chromecast {
-namespace shell {
-
-class ChromecastBrowserTestHelper {
- public:
-  // Creates an implementation of ChromecastBrowserTestHelper. Allows public
-  // and internal builds to instantiate different implementations.
-  static std::unique_ptr<ChromecastBrowserTestHelper> Create();
-
-  virtual ~ChromecastBrowserTestHelper() {}
-  virtual content::WebContents* NavigateToURL(const GURL& url) = 0;
-  virtual void BlockMediaLoading(bool block) = 0;
-};
-
-}  // namespace shell
-}  // namespace chromecast
-
-#endif  // CHROMECAST_BROWSER_TEST_CHROMECAST_BROWSER_TEST_HELPER_H_