components: Cleanup class/struct fwd declarations

components/sync_sessions/revisit/bookmarks_page_revisit_observer.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_SYNC_SESSIONS_REVISIT_BOOKMARKS_PAGE_REVISIT_OBSERVER_H_
 #define COMPONENTS_SYNC_SESSIONS_REVISIT_BOOKMARKS_PAGE_REVISIT_OBSERVER_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "components/sync_sessions/revisit/page_visit_observer.h"
 
 class GURL;
 
 namespace bookmarks {
-class BookmarkModel;
 class BookmarkNode;
 }  // namespace bookmarks
 
 namespace sync_sessions {
 
 // A simple interface to abstract away who is providing bookmarks.
 class BookmarksByUrlProvider {
  public:
   // Fills the passed vector with all bookmark nodes for the given URL.
   virtual void GetNodesByURL(
@@ skipping 17 matching lines @@
   void OnPageVisit(const GURL& url, const TransitionType transition) override;
 
  private:
   std::unique_ptr<BookmarksByUrlProvider> provider_;
   DISALLOW_COPY_AND_ASSIGN(BookmarksPageRevisitObserver);
 };
 
 }  // namespace sync_sessions
 
 #endif  // COMPONENTS_SYNC_SESSIONS_REVISIT_BOOKMARKS_PAGE_REVISIT_OBSERVER_H_