Cleanup: Remove unneeded forward declarations from various chrome/browser subdirectories.

chrome/browser/download/download_request_infobar_delegate.h

 // Copyright (c) 2011 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_REQUEST_INFOBAR_DELEGATE_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_INFOBAR_DELEGATE_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "chrome/browser/download/download_request_limiter.h"
 #include "chrome/browser/tab_contents/confirm_infobar_delegate.h"
 
-class TabContents;
-
 // An infobar delegate that presents the user with a choice to allow or deny
 // multiple downloads from the same site. This confirmation step protects
 // against "carpet-bombing", where a malicious site forces multiple downloads
 // on an unsuspecting user.
 class DownloadRequestInfoBarDelegate : public ConfirmInfoBarDelegate {
  public:
   DownloadRequestInfoBarDelegate(
       InfoBarTabHelper* infobar_helper,
       DownloadRequestLimiter::TabDownloadState* host);
 
   void set_host(DownloadRequestLimiter::TabDownloadState* host) {
     host_ = host;
   }
 
  private:
   virtual ~DownloadRequestInfoBarDelegate();
 
   // ConfirmInfoBarDelegate:
   virtual gfx::Image* GetIcon() const OVERRIDE;
   virtual string16 GetMessageText() const OVERRIDE;
   virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
 
   DownloadRequestLimiter::TabDownloadState* host_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadRequestInfoBarDelegate);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_INFOBAR_DELEGATE_H_