Revert of Implement IPC::ParamTraits<mojo::MessagePipeHandle>

ipc/mojo/ipc_mojo_param_traits.cc

-// Copyright 2015 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.
-
-#include "ipc/mojo/ipc_mojo_param_traits.h"
-
-#include "ipc/ipc_message_utils.h"
-#include "ipc/mojo/ipc_mojo_message_helper.h"
-
-namespace IPC {
-
-void ParamTraits<mojo::MessagePipeHandle>::Write(Message* m,
-                                                 const param_type& p) {
-  WriteParam(m, p.is_valid());
-  if (p.is_valid())
-    MojoMessageHelper::WriteMessagePipeTo(m, mojo::ScopedMessagePipeHandle(p));
-}
-
-bool ParamTraits<mojo::MessagePipeHandle>::Read(const Message* m,
-                                                PickleIterator* iter,
-                                                param_type* r) {
-  bool is_valid;
-  if (!ReadParam(m, iter, &is_valid))
-    return false;
-  if (!is_valid)
-    return true;
-
-  mojo::ScopedMessagePipeHandle handle;
-  if (!MojoMessageHelper::ReadMessagePipeFrom(m, iter, &handle))
-    return false;
-  *r = handle.release();
-  return true;
-}
-
-void ParamTraits<mojo::MessagePipeHandle>::Log(const param_type& p,
-                                               std::string* l) {
-  l->append("mojo::MessagePipeHandle(");
-  LogParam(p.value(), l);
-  l->append(")");
-}
-
-}  // namespace IPC