extensions: Cleanup class/struct fwd declarations

extensions/browser/guest_view/extension_options/extension_options_guest.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_GUEST_VIEW_EXTENSION_OPTIONS_EXTENSION_OPTIONS_GUEST_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_EXTENSION_OPTIONS_EXTENSION_OPTIONS_GUEST_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "components/guest_view/browser/guest_view.h"
 #include "extensions/browser/guest_view/extension_options/extension_options_guest_delegate.h"
 #include "url/gurl.h"
 
-namespace content {
-class BrowserContext;
-}
-
 namespace extensions {
 
 class ExtensionOptionsGuest
     : public guest_view::GuestView<ExtensionOptionsGuest> {
  public:
   static const char Type[];
   static guest_view::GuestViewBase* Create(
       content::WebContents* owner_web_contents);
 
  private:
@@ skipping 36 matching lines @@
   std::unique_ptr<extensions::ExtensionOptionsGuestDelegate>
       extension_options_guest_delegate_;
   GURL options_page_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionOptionsGuest);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_EXTENSION_OPTIONS_EXTENSION_OPTIONS_GUEST_H_