chrome: Cleanup class/struct forward declarations

chrome/browser/download/download_target_determiner_delegate.h

 // Copyright 2013 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 CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_DETERMINER_DELEGATE_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_DETERMINER_DELEGATE_H_
 
 #include "base/callback_forward.h"
 
 #include "chrome/browser/download/download_path_reservation_tracker.h"
 #include "content/public/browser/download_danger_type.h"
 
-class ExtensionDownloadsEventRouter;
-
 namespace base {
 class FilePath;
 }
 
 namespace content {
 class DownloadItem;
 }
 
 // Delegate for DownloadTargetDeterminer. The delegate isn't owned by
 // DownloadTargetDeterminer and is expected to outlive it.
@@ skipping 91 matching lines @@
                                 const CheckDownloadUrlCallback& callback) = 0;
 
   // Get the MIME type for the given file.
   virtual void GetFileMimeType(const base::FilePath& path,
                                const GetFileMimeTypeCallback& callback) = 0;
  protected:
   virtual ~DownloadTargetDeterminerDelegate();
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_DETERMINER_DELEGATE_H_