content: Cleanup class/struct forward declarations

chrome/browser/prerender/prerender_contents.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 "chrome/browser/prerender/prerender_contents.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <functional>
@@ skipping 28 matching lines @@
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/resource_request_details.h"
 #include "content/public/browser/session_storage_namespace.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/frame_navigate_params.h"
 #include "ui/base/page_transition_types.h"
 #include "ui/gfx/geometry/size.h"
 
 using content::BrowserThread;
-using content::DownloadItem;
 using content::OpenURLParams;
 using content::RenderViewHost;
 using content::ResourceRedirectDetails;
 using content::ResourceType;
 using content::SessionStorageNamespace;
 using content::WebContents;
 
 namespace prerender {
 
 namespace {
@@ skipping 693 matching lines @@
 void PrerenderContents::AddResourceThrottle(
     const base::WeakPtr<PrerenderResourceThrottle>& throttle) {
   resource_throttles_.push_back(throttle);
 }
 
 void PrerenderContents::AddNetworkBytes(int64_t bytes) {
   network_bytes_ += bytes;
 }
 
 }  // namespace prerender