Mojo C++ bindings: support mapping mojo string to WTF::String.

mojo/public/cpp/bindings/lib/bindings_serialization.h

 // Copyright 2013 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 94 matching lines @@
 inline void AssociatedInterfaceDataToPtrInfo(
     AssociatedInterface_Data* input,
     AssociatedInterfacePtrInfo<T>* output,
     MultiplexRouter* router) {
   AssociatedInterfacePtrInfoHelper::SetHandle(
       output,
       router->CreateLocalEndpointHandle(FetchAndReset(&input->interface_id)));
   output->set_version(input->version);
 }
 
+class WTFStringContext {
+ public:
+  virtual ~WTFStringContext() {}
+};
+
 // Context information for serialization/deserialization routines.
 struct SerializationContext {
   SerializationContext();
   explicit SerializationContext(scoped_refptr<MultiplexRouter> in_router);
 
   ~SerializationContext();
 
   // Used to serialize/deserialize associated interface pointers and requests.
   scoped_refptr<MultiplexRouter> router;
+
+  scoped_ptr<WTFStringContext> wtf_string_context;
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_