Separates ipc code from common (http://crbug.com/16829)

ipc/ipc_channel_handle.h

Index: ipc/ipc_channel_handle.h
diff --git a/ipc/ipc_channel_handle.h b/ipc/ipc_channel_handle.h
new file mode 100644
index 0000000000000000000000000000000000000000..e3b2f3e7ba1d033767b77b960ab4ff7f2a508a14
--- /dev/null
+++ b/ipc/ipc_channel_handle.h
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+// Copyright (c) 2009 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_IPC_CHANNEL_HANDLE_H_
+#define IPC_IPC_CHANNEL_HANDLE_H_
+
+#include "build/build_config.h"
+
+#if defined(OS_POSIX)
+#include "base/file_descriptor_posix.h"
+#endif
+
+// On Windows, any process can create an IPC channel and others can fetch
+// it by name.  We pass around the channel names over IPC.
+// On POSIX, we instead pass around handles to channel endpoints via IPC.
+// When it's time to IPC a new channel endpoint around, we send both the
+// channel name as well as a base::FileDescriptor, which is itself a special
+// type that knows how to copy a socket endpoint over IPC.
+//
+// In sum, when passing a handle to a channel over IPC, use this data structure
+// to work on both Windows and POSIX.
+
+namespace IPC {
+
+struct ChannelHandle {
+  // Note that serialization for this object is defined in the ParamTraits
+  // template specialization in ipc_message_utils.h.
+  std::string name;
+#if defined(OS_POSIX)
+  base::FileDescriptor socket;
+#endif
+
+  ChannelHandle() {}
+#if defined(OS_POSIX)
+  ChannelHandle(const std::string& n, const base::FileDescriptor& s)
+      : name(n), socket(s) {}
+#else
+  ChannelHandle(const std::string& n) : name(n) {}
+#endif
+};
+
+}  // namespace IPC
+
+#endif  // IPC_IPC_CHANNEL_HANDLE_H_