net: Add NET_API to a few more files.

net/proxy/dhcp_proxy_script_fetcher_factory.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.
 
 #ifndef NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_
 #define NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
 #include "net/base/completion_callback.h"
+#include "net/base/net_api.h"
 #include "net/url_request/url_request_context.h"
 
 namespace net {
 
 class DhcpProxyScriptFetcher;
 
 // Factory object for creating the appropriate concrete base class of
 // DhcpProxyScriptFetcher for your operating system and settings.
 //
 // You might think we could just implement a DHCP client at the protocol
 // level and have cross-platform support for retrieving PAC configuration
 // from DHCP, but unfortunately the DHCP protocol assumes there is a single
 // client per machine (specifically per network interface card), and there
 // is an implicit state machine between the client and server, so adding a
 // second client to the machine would not be advisable (see e.g. some
 // discussion of what can happen at this URL:
 // http://www.net.princeton.edu/multi-dhcp-one-interface-handling.html).
 //
 // Therefore, we have platform-specific implementations, and so we use
 // this factory to select the right one.
-class DhcpProxyScriptFetcherFactory {
+class NET_API DhcpProxyScriptFetcherFactory {

[wtc, 2011/05/20 22:21:19]

I am surprised that DhcpProxyScriptFetcherFactory needs to
be exposed to the user of our network stack.  This is a sign
that we leak too many implementation details.

Is this used by the IOThread to set up the various
URLRequestContext objects?

[rvargas (doing something else), 2011/05/20 22:54:55]

chrome/browser/net/connection_tester.cc and
chrome/browser/net/proxy_service_factory.cc use it to setup the proxy service.

On 2011/05/20 22:21:19, wtc wrote:

  public:
   // Creates a new factory object with default settings.
   DhcpProxyScriptFetcherFactory();
 
   // Ownership is transferred to the caller. url_request_context must be valid
   // and its lifetime must exceed that of the returned DhcpProxyScriptFetcher.
   //
   // Note that while a request is in progress, the fetcher may be holding a
   // reference to |url_request_context|. Be careful not to create cycles
   // between the fetcher and the context; you can break such cycles by calling
@@ skipping 16 matching lines @@
 
  protected:
   bool feature_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(DhcpProxyScriptFetcherFactory);
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_