components: Cleanup class/struct fwd declarations

components/dom_distiller/content/browser/dom_distiller_viewer_source.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 COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DOM_DISTILLER_VIEWER_SOURCE_H_
 #define COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DOM_DISTILLER_VIEWER_SOURCE_H_
 
 #include <memory>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "components/dom_distiller/content/browser/distiller_ui_handle.h"
 #include "content/public/browser/url_data_source.h"
 
 namespace dom_distiller {
 
 class DomDistillerServiceInterface;
 class DomDistillerViewerSourceTest;
-class ViewerHandle;
-class ViewRequestDelegate;
 
 // Serves HTML and resources for viewing distilled articles.
 class DomDistillerViewerSource : public content::URLDataSource {
  public:
   DomDistillerViewerSource(DomDistillerServiceInterface* dom_distiller_service,
                            const std::string& scheme,
                            std::unique_ptr<DistillerUIHandle> ui_handle);
   ~DomDistillerViewerSource() override;
 
   class RequestViewerHandle;
@@ skipping 24 matching lines @@
   // An object for accessing chrome-specific UI controls including external
   // feedback and opening the distiller settings.
   std::unique_ptr<DistillerUIHandle> distiller_ui_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(DomDistillerViewerSource);
 };
 
 }  // namespace dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DOM_DISTILLER_VIEWER_SOURCE_H_