Revert "Clean up dns prefetch code, and also port it."

chrome/browser/net/dns_slave.h

+// Copyright (c) 2006-2008 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.
+
+// A DnsSlave object processes hostname lookups
+// via DNS on a single thread, waiting for that blocking
+// call to complete, and then getting its next hostname
+// from its associated DnsMaster object.
+// Since this class only is concerned with prefetching
+// to warm the underlying DNS cache, the actual IP
+// does not need to be recorded.  It is necessary to record
+// when the lookup finished, so that the associated DnsMaster
+// won't (wastefully) ask for the same name in "too short a
+// period of time."
+// This class does no "de-duping," and merely slavishly services
+// items supplied by its DnsMaster.
+
+#ifndef CHROME_BROWSER_NET_DNS_SLAVE_H_
+#define CHROME_BROWSER_NET_DNS_SLAVE_H_
+
+#include <windows.h>
+#include <string>
+
+#include "base/basictypes.h"
+
+namespace chrome_browser_net {
+
+class DnsMaster;
+class DnsSlave;
+
+// Support testing infrastructure, and allow off-line testing.
+typedef void (__stdcall *FreeAddrInfoFunction)(struct addrinfo* ai);
+typedef int (__stdcall *GetAddrInfoFunction)(const char* nodename,
+                                             const char* servname,
+                                             const struct addrinfo* hints,
+                                             struct addrinfo** result);
+void SetAddrinfoCallbacks(GetAddrInfoFunction getaddrinfo,
+                          FreeAddrInfoFunction freeaddrinfo);
+
+GetAddrInfoFunction get_getaddrinfo();
+FreeAddrInfoFunction get_freeaddrinfo();
+
+class DnsSlave {
+ public:
+  DnsSlave(DnsMaster* master, size_t slave_index)
+      : master_(master),
+        slave_index_(slave_index) {
+  }
+
+  ~DnsSlave() {
+    master_ = NULL;
+  }
+
+  static DWORD WINAPI ThreadStart(void* pThis);
+
+  unsigned Run();
+
+ private:
+  std::string hostname_;  // Name being looked up.
+
+  DnsMaster* master_;  // Master that started us.
+  size_t slave_index_;  // Our index into DnsMaster's array.
+
+  void BlockingDnsLookup();
+
+  DISALLOW_COPY_AND_ASSIGN(DnsSlave);
+};
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_DNS_SLAVE_H_
+