IPC: Add new classes required for attachment brokering.

ipc/handle_attachment_win.h

Index: ipc/handle_attachment_win.h
diff --git a/ipc/handle_attachment_win.h b/ipc/handle_attachment_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..b539907e8283e48f32b28bdfd98b0b892b551a31
--- /dev/null
+++ b/ipc/handle_attachment_win.h
@@ -0,0 +1,24 @@
+// 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.
+
+#ifndef IPC_HANDLE_ATTACHMENT_WIN_H_
+#define IPC_HANDLE_ATTACHMENT_WIN_H_
+
+#include "ipc/brokerable_attachment.h"
+#include "ipc/ipc_export.h"
+
+namespace IPC {
+namespace internal {
+
+// This class represents a Windows HANDLE attached to a Chrome IPC message.
+class IPC_EXPORT HandleAttachmentWin : public BrokerableAttachment {
+ private:
+  Type GetType() const override { return TYPE_WIN_HANDLE; }
+  HANDLE handle_;
+};
+
+}  // namespace internal
+}  // namespace IPC
+
+#endif  // IPC_HANDLE_ATTACHMENT_WIN_H_