chrome: Cleanup class/struct forward declarations

chrome/browser/safe_browsing/threat_details_cache.h

 // 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.
 
 #ifndef CHROME_BROWSER_SAFE_BROWSING_THREAT_DETAILS_CACHE_H_
 #define CHROME_BROWSER_SAFE_BROWSING_THREAT_DETAILS_CACHE_H_
 
 // A class that gets threat details from the HTTP Cache.
 // An instance of this class is generated by ThreatDetails.
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/common/safe_browsing/csd.pb.h"
 #include "net/base/completion_callback.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
 namespace net {
 class URLFetcher;
-class URLRequestContext;
 }
 
 namespace safe_browsing {
 
 // Maps a URL to its Resource.
 typedef base::hash_map<
     std::string,
     linked_ptr<ClientSafeBrowsingReportRequest::Resource>>
     ResourceMap;
 
@@ skipping 68 matching lines @@
   // Called when we are done.
   void AllDone(bool success);
 
   // Advances to the next entry in resources_it_.
   void AdvanceEntry();
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_THREAT_DETAILS_CACHE_H_