Really remove io support when dart:io is unsupported.

runtime/bin/socket.h

 // 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.
 
 #ifndef BIN_SOCKET_H_
 #define BIN_SOCKET_H_
 
-#include <map>
+#if defined(DART_IO_DISABLED)

[Bill Hesse, 2016/03/30 09:50:27]

This error is being hit on Windows compilations of Dartium.
So Dartium is broken since this commit.

+#error "socket.h can only be included on builds with IO enabled"
+#endif
 
 #include "platform/globals.h"
-
-#include "bin/builtin.h"
-#include "bin/dartutils.h"
 // Declare the OS-specific types ahead of defining the generic class.
 #if defined(TARGET_OS_ANDROID)
 #include "bin/socket_android.h"
 #elif defined(TARGET_OS_LINUX)
 #include "bin/socket_linux.h"
 #elif defined(TARGET_OS_MACOS)
 #include "bin/socket_macos.h"
 #elif defined(TARGET_OS_WINDOWS)
 #include "bin/socket_win.h"
 #else
 #error Unknown target os.
 #endif
+
+#include <map>
+
+#include "bin/builtin.h"
+#include "bin/dartutils.h"
 #include "bin/thread.h"
 #include "bin/utils.h"
 
 namespace dart {
 namespace bin {
 
 union RawAddr {
   struct sockaddr_in in;
   struct sockaddr_in6 in6;
   struct sockaddr_storage ss;
@@ skipping 396 matching lines @@
   typedef std::map<intptr_t, OSSocket*>::iterator SocketsIterator;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ListeningSocketRegistry);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_SOCKET_H_