services: Cleanup class/struct fwd declarations

services/navigation/navigation.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 SERVICES_NAVIGATION_NAVIGATION_H_
 #define SERVICES_NAVIGATION_NAVIGATION_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
 #include "content/public/common/connection_filter.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/navigation/public/interfaces/view.mojom.h"
 #include "services/service_manager/public/cpp/interface_factory.h"
 #include "services/service_manager/public/cpp/service.h"
 #include "services/service_manager/public/cpp/service_context_ref.h"
 
-namespace content {
-class BrowserContext;
-}
-
 namespace navigation {
 
 std::unique_ptr<service_manager::Service> CreateNavigationService();
 
 class Navigation : public service_manager::Service, public mojom::ViewFactory {
  public:
   Navigation();
   ~Navigation() override;
 
  private:
@@ skipping 18 matching lines @@
   mojo::BindingSet<mojom::ViewFactory> bindings_;
 
   base::WeakPtrFactory<Navigation> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Navigation);
 };
 
 }  // navigation
 
 #endif  // SERVICES_NAVIGATION_NAVIGATION_H_