extensions: Cleanup class/struct fwd declarations

extensions/browser/api/socket/socket_api.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_API_SOCKET_SOCKET_API_H_
 #define EXTENSIONS_BROWSER_API_SOCKET_SOCKET_API_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 17 matching lines @@
 #endif  // OS_CHROMEOS
 
 namespace content {
 class BrowserContext;
 class ResourceContext;
 }
 
 namespace net {
 class IOBuffer;
 class URLRequestContextGetter;
-class SSLClientSocket;
 }
 
 namespace extensions {
 class Socket;
 class TLSSocket;
 
 // A simple interface to ApiResourceManager<Socket> or derived class. The goal
 // of this interface is to allow Socket API functions to use distinct instances
 // of ApiResourceManager<> depending on the type of socket (old version in
 // "socket" namespace vs new version in "socket.xxx" namespaces).
@@ skipping 507 matching lines @@
 
   std::unique_ptr<api::socket::Secure::Params> params_;
   scoped_refptr<net::URLRequestContextGetter> url_request_getter_;
 
   DISALLOW_COPY_AND_ASSIGN(SocketSecureFunction);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_SOCKET_SOCKET_API_H_