chrome: Cleanup class/struct forward declarations

chrome/browser/android/download/duplicate_download_infobar_delegate.h

 // Copyright 2016 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_ANDROID_DOWNLOAD_DUPLICATE_DOWNLOAD_INFOBAR_DELEGATE_H_
 #define CHROME_BROWSER_ANDROID_DOWNLOAD_DUPLICATE_DOWNLOAD_INFOBAR_DELEGATE_H_
 
 #include "components/infobars/core/confirm_infobar_delegate.h"
 
-class InfoBarService;
-
 namespace chrome {
 namespace android {
 
 // An infobar that asks if user wants to continue downloading when there is
 // already a duplicate file in storage. If user chooses to proceed,
 // a new file will be created.
 // Note that this infobar does not expire if the user subsequently navigates,
 // since such navigations won't automatically cancel the underlying download.
 class DuplicateDownloadInfoBarDelegate : public ConfirmInfoBarDelegate {
  public:
   // Gets the file path to be downloaded.
   virtual std::string GetFilePath() const = 0;
 
   // Whether the download is for offline page.
   virtual bool IsOfflinePage() const;
 
   virtual std::string GetPageURL() const;
 
   virtual bool IsOffTheRecord() const;
 
   // ConfirmInfoBarDelegate implementation.
   base::string16 GetMessageText() const override;
   bool ShouldExpire(const NavigationDetails& details) const override;
 };
 
 }  // namespace android
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_DOWNLOAD_DUPLICATE_DOWNLOAD_INFOBAR_DELEGATE_H_