Make PlatformFileForTransit its own class on Windows.

ipc/ipc_message_utils.h

Index: ipc/ipc_message_utils.h
diff --git a/ipc/ipc_message_utils.h b/ipc/ipc_message_utils.h
index 847a617c8334ee33bfa54adab77c3d252081476f..dd6755e04a0edf4ebfa3582b9d3559f49e198283 100644
--- a/ipc/ipc_message_utils.h
+++ b/ipc/ipc_message_utils.h
@@ -49,6 +49,10 @@ namespace IPC {
 
 struct ChannelHandle;
 
+#if defined(OS_WIN)
+class PlatformFileForTransit;
+#endif
+
 // -----------------------------------------------------------------------------
 // How we send IPC message logs across channels.
 struct IPC_EXPORT LogData {
@@ -593,6 +597,19 @@ struct IPC_EXPORT ParamTraits<base::SharedMemoryHandle> {
   static void Log(const param_type& p, std::string* l);
 };
 
+#if defined(OS_WIN)
+template <>
+struct IPC_EXPORT ParamTraits<PlatformFileForTransit> {
+  typedef PlatformFileForTransit param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
+  static void Write(base::Pickle* m, const param_type& p);
+  static bool Read(const base::Pickle* m,
+                   base::PickleIterator* iter,
+                   param_type* r);
+  static void Log(const param_type& p, std::string* l);
+};
+#endif  // defined(OS_WIN)
+
 template <>
 struct IPC_EXPORT ParamTraits<base::FilePath> {
   typedef base::FilePath param_type;