Adds support for the DHCP portion of the WPAD (proxy auto-discovery) protocol.

This is Windows-only for now, and is disabled by default.  Start
Chrome with the flag --enable-dhcp-wpad to enable the feature.  See
discussion in comment on DhcpProxyScriptFetcherFactory for why this
needs to be done in a per-platform way rather than cross-platform.
The code is factored so that adding other platform implementations
will be straight forward.

Most of the implementation is stand-alone and extends the
ScriptProxyFetcher class hierarchy (and makes its interface slightly
more generic).  The integration point into existing code is in
InitProxyResolver, which previously handled fallback from DNS
auto-detect to custom PAC URL and now does fallback from DHCP to DNS
to custom PAC URL.

BUG=18575
TEST=net_unittests has good coverage for the new and changed code, but
manual tests on a network with a PAC URL configured in DHCP are also
needed.

Review URL: http://codereview.chromium.org/6831025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@85646 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 40 insertions, 0 deletions

diff --git a/net/proxy/dhcpcsvc_init_win.cc b/net/proxy/dhcpcsvc_init_win.cc
new file mode 100644
index 0000000..3a0aa02
--- /dev/null
+++ b/net/proxy/dhcpcsvc_init_win.cc
@@ -0,0 +1,40 @@
+// 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.
+
+#include "net/proxy/dhcpcsvc_init_win.h"
+
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+
+#include <dhcpcsdk.h>
+#include <dhcpv6csdk.h>
+
+namespace {
+
+class DhcpcsvcInitSingleton {
+ public:
+  DhcpcsvcInitSingleton() {
+    DWORD version = 0;
+    DWORD err = DhcpCApiInitialize(&version);
+    DCHECK(err == ERROR_SUCCESS);  // DCHECK_EQ complains of unsigned mismatch.
+  }
+
+  ~DhcpcsvcInitSingleton() {
+    // Worker pool threads that use the DHCP API may still be running, so skip
+    // cleanup.
+  }
+};
+
+static base::LazyInstance<DhcpcsvcInitSingleton> g_dhcpcsvc_init_singleton(
+    base::LINKER_INITIALIZED);
+
+}  // namespace
+
+namespace net {
+
+void EnsureDhcpcsvcInit() {
+  g_dhcpcsvc_init_singleton.Get();
+}
+
+}  // namespace net