IPC: Add new classes required for attachment brokering.

ipc/attachment_broker_win.h

Index: ipc/attachment_broker_win.h
diff --git a/ipc/attachment_broker_win.h b/ipc/attachment_broker_win.h
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+// 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_ATTACHMENT_BROKER_WIN_H_
+#define IPC_ATTACHMENT_BROKER_WIN_H_
+
+#include "ipc/attachment_broker.h"
+#include "ipc/ipc_export.h"
+#include "ipc/ipc_sender.h"
+
+namespace IPC {
+
+// This class is an implementation of AttachmentBroker for the Windows platform.
+class IPC_EXPORT AttachmentBrokerWin : public IPC::AttachmentBroker {
+ public:
+  AttachmentBrokerWin();
+  virtual ~AttachmentBrokerWin();
+
+  // In a non-broker process, the single instance of this class listens for
+  // an IPC from the broker process indicating that a new attachment has been
+  // duplicated.
+  void OnReceiveDuplicatedHandle(HANDLE, BrokerableAttachmentId id);
+
+  // IPC::AttachmentBroker overrides.
+  void SendAttachmentToProcess(BrokerableAttachment* attachment,
+                               base::ProcessId destination_process) override;
+  bool GetAttachmentWithId(BrokerableAttachmentId id,
+                           BrokerableAttachment* attachment) override;
+};
+
+}  // namespace IPC
+
+#endif  // IPC_ATTACHMENT_BROKER_WIN_H_