It suffices to just forward-declare DnsCertProvenanceChecker

net/url_request/url_request_context.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.
 
 // This class represents contextual information (cookies, cache, etc.)
 // that's useful when processing resource requests.
 // The class is reference-counted so that it can be cleaned up after any
 // requests that are using it have been completed.
 
 #ifndef NET_URL_REQUEST_URL_REQUEST_CONTEXT_H_
 #define NET_URL_REQUEST_URL_REQUEST_CONTEXT_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/threading/non_thread_safe.h"
 #include "net/base/net_api.h"
 #include "net/base/net_log.h"
 #include "net/base/ssl_config_service.h"
 #include "net/base/transport_security_state.h"
 #include "net/ftp/ftp_auth_cache.h"
-#include "net/socket/dns_cert_provenance_checker.h"

[wtc, 2011/05/24 14:53:37]

We only need the forward declaration on line 26.

 
 namespace net {
 class CertVerifier;
 class CookieStore;
 class DnsCertProvenanceChecker;
 class DnsRRResolver;
 class FtpTransactionFactory;
 class HostResolver;
 class HttpAuthHandlerFactory;
 class HttpTransactionFactory;
 class NetworkDelegate;
 class ProxyService;
-class SSLConfigService;

[wtc, 2011/05/24 14:53:37]

We include "net/base/ssl_config_service.h" on line 18, so
this forward declaration is not necessary.

 class URLRequest;
 class URLRequestJobFactory;
 
 // Subclass to provide application-specific context for URLRequest
 // instances. Note that URLRequestContext typically does not provide storage for
 // these member variables, since they may be shared. For the ones that aren't
 // shared, URLRequestContextStorage can be helpful in defining their storage.
 class NET_API URLRequestContext
     : public base::RefCountedThreadSafe<URLRequestContext>,
       NON_EXPORTED_BASE(public base::NonThreadSafe) {
@@ skipping 168 matching lines @@
   // Important: When adding any new members below, consider whether they need to
   // be added to CopyFrom.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(URLRequestContext);
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_CONTEXT_H_