Add support for threadsafe completion callback factory.

ppapi/cpp/websocket.h

 // Copyright (c) 2012 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 PPAPI_CPP_WEBSOCKET_H_
 #define PPAPI_CPP_WEBSOCKET_H_
 
 #include "ppapi/c/ppb_websocket.h"
 #include "ppapi/cpp/resource.h"
 
 /// @file
 /// This file defines the WebSocket interface providing bi-directional,
 /// full-duplex, communications over a single TCP socket.
 
+// Windows headers will redefine SendMessage.
+#ifdef SendMessage
+#undef SendMessage
+#endif
+
 namespace pp {
 
 class CompletionCallback;
 class InstanceHandle;
 class Var;
 
 /// The <code>WebSocket</code> class providing bi-directional,
 /// full-duplex, communications over a single TCP socket.
 class WebSocket : public Resource {
  public:
@@ skipping 179 matching lines @@
   /// @return Returns a <code>Var</code> of string type. If called before the
   /// connection is established, the <code>Var</code> contains the empty
   /// string. Returns a <code>PP_VARTYPE_UNDEFINED</code> if this function
   /// is called on an invalid resource.
   Var GetURL();
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_WEBSOCKET_H_