Add a Mojo EDK for Chrome that uses one OS pipe per message pipe.

ipc/mojo/ipc_mojo_handle_attachment.cc

 // Copyright (c) 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_handle_attachment.h"
 
 #include "ipc/ipc_message_attachment_set.h"
+
+#if defined(USE_CHROME_EDK)
+#include "mojo/edk/embedder/embedder.h"
+#else
 #include "third_party/mojo/src/mojo/edk/embedder/embedder.h"
+#endif
 
 namespace IPC {
 namespace internal {
 
 MojoHandleAttachment::MojoHandleAttachment(mojo::ScopedHandle handle)
     : handle_(handle.Pass()) {
 }
 
 MojoHandleAttachment::~MojoHandleAttachment() {
 }
@@ skipping 16 matching lines @@
   return platform_handle.release().fd;
 }
 #endif  // OS_POSIX
 
 mojo::ScopedHandle MojoHandleAttachment::TakeHandle() {
   return handle_.Pass();
 }
 
 }  // namespace internal
 }  // namespace IPC