Remove unused fields from //content.

content/browser/download/download_manager_impl.cc

 // Copyright (c) 2012 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.
 
 #include "content/browser/download/download_manager_impl.h"
 
 #include <iterator>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 167 matching lines @@
   }
 };
 
 }  // namespace
 
 DownloadManagerImpl::DownloadManagerImpl(
     net::NetLog* net_log,
     BrowserContext* browser_context)
     : item_factory_(new DownloadItemFactoryImpl()),
       file_factory_(new DownloadFileFactory()),
-      history_size_(0),
       shutdown_needed_(true),
       browser_context_(browser_context),
       delegate_(NULL),
       net_log_(net_log),
       weak_factory_(this) {
   DCHECK(browser_context);
 }
 
 DownloadManagerImpl::~DownloadManagerImpl() {
   DCHECK(!shutdown_needed_);
@@ skipping 521 matching lines @@
   if (delegate_)
     delegate_->OpenDownload(download);
 }
 
 void DownloadManagerImpl::ShowDownloadInShell(DownloadItemImpl* download) {
   if (delegate_)
     delegate_->ShowDownloadInShell(download);
 }
 
 }  // namespace content