Re-land socket refactor with fixes for Windows.

runtime/bin/eventhandler_win.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(HOST_OS_WINDOWS)
 
 #include "bin/eventhandler.h"
@@ skipping 1552 matching lines @@
   }
 
   {
     MonitorLocker ml(startup_monitor_);
     while (handler_thread_id_ == Thread::kInvalidThreadId) {
       ml.Wait();
     }
   }
 
   // Initialize Winsock32
-  if (!Socket::Initialize()) {
+  if (!SocketBase::Initialize()) {
     FATAL("Failed to initialized Windows sockets");
   }
 }
 
 
 void EventHandlerImplementation::Shutdown() {
   SendData(kShutdownId, 0, 0);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(HOST_OS_WINDOWS)
 
 #endif  // !defined(DART_IO_DISABLED)