blimp: Cleanup class/struct forward declarations

blimp/client/core/contents/blimp_contents_impl.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 BLIMP_CLIENT_CORE_CONTENTS_BLIMP_CONTENTS_IMPL_H_
 #define BLIMP_CLIENT_CORE_CONTENTS_BLIMP_CONTENTS_IMPL_H_
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "blimp/client/core/contents/blimp_contents_view_impl.h"
@@ skipping 11 matching lines @@
 
 namespace blimp {
 namespace client {
 
 #if defined(OS_ANDROID)
 class BlimpContentsImplAndroid;
 #endif  // defined(OS_ANDROID)
 
 class BlimpCompositorDependencies;
 class BlimpContentsObserver;
-class BlimpNavigationController;
 class ImeFeature;
 class NavigationFeature;
 class RenderWidgetFeature;
 class TabControlFeature;
 
 class BlimpContentsImpl : public BlimpContents,
                           public BlimpNavigationControllerDelegate {
  public:
   // Ownership of the features remains with the caller.
   // |window| must be the platform specific window that this will be shown in.
@@ skipping 72 matching lines @@
   // from the BlimpContents.
   std::unique_ptr<BlimpContentsViewImpl> blimp_contents_view_;
 
   DISALLOW_COPY_AND_ASSIGN(BlimpContentsImpl);
 };
 
 }  // namespace client
 }  // namespace blimp
 
 #endif  // BLIMP_CLIENT_CORE_CONTENTS_BLIMP_CONTENTS_IMPL_H_