components: Cleanup class/struct fwd declarations

components/contextual_search/renderer/contextual_search_wrapper.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 COMPONENTS_CONTEXTUAL_SEARCH_RENDERER_CONTEXTUAL_SEARCH_WRAPPER_H_
 #define COMPONENTS_CONTEXTUAL_SEARCH_RENDERER_CONTEXTUAL_SEARCH_WRAPPER_H_
 
 #include "base/macros.h"
 #include "components/contextual_search/common/contextual_search_js_api_service.mojom.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "gin/handle.h"
 #include "gin/wrappable.h"
 
 namespace blink {
 class WebFrame;
 }
 
-namespace gin {
-class Arguments;
-}
-
 namespace contextual_search {
 
 // Wrapper for injecting Contextual Search JavaScript
 // into a WebFrame.
 class ContextualSearchWrapper : public gin::Wrappable<ContextualSearchWrapper>,
                                 public content::RenderFrameObserver {
  public:
   // Installs Contextual Search JavaScript.
   static void Install(content::RenderFrame* render_frame);
 
@@ skipping 23 matching lines @@
 
   // The service to notify when API calls are made.
   mojom::ContextualSearchJsApiServicePtr contextual_search_js_api_service_;
 
   DISALLOW_COPY_AND_ASSIGN(ContextualSearchWrapper);
 };
 
 }  // namespace contextual_search
 
 #endif  // COMPONENTS_CONTEXTUAL_SEARCH_RENDERER_CONTEXTUAL_SEARCH_WRAPPER_H_