chrome: Cleanup class/struct forward declarations

chrome/test/media_router/media_router_integration_browsertest.h

 // 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.
 
 #ifndef CHROME_TEST_MEDIA_ROUTER_MEDIA_ROUTER_INTEGRATION_BROWSERTEST_H_
 #define CHROME_TEST_MEDIA_ROUTER_MEDIA_ROUTER_INTEGRATION_BROWSERTEST_H_
 
 #include <memory>
 #include <string>
 
 #include "base/debug/stack_trace.h"
 #include "base/files/file_path.h"
 #include "chrome/browser/ui/toolbar/media_router_action.h"
 #include "chrome/test/media_router/media_router_base_browsertest.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/test_navigation_observer.h"
 
 
 namespace media_router {
 
-class MediaRouter;
-
 class MediaRouterIntegrationBrowserTest : public MediaRouterBaseBrowserTest {
  public:
   MediaRouterIntegrationBrowserTest();
   ~MediaRouterIntegrationBrowserTest() override;
 
  protected:
   // InProcessBrowserTest Overrides
   void TearDownOnMainThread() override;
 
   // MediaRouterBaseBrowserTest Overrides
@@ skipping 106 matching lines @@
 
   std::unique_ptr<content::TestNavigationObserver> test_navigation_observer_;
 
   // Fields
   std::string receiver_;
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_TEST_MEDIA_ROUTER_MEDIA_ROUTER_INTEGRATION_BROWSERTEST_H_