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diff --git a/ipc/glue/IPDLParamTraits.h b/ipc/glue/IPDLParamTraits.h
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+++ b/ipc/glue/IPDLParamTraits.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ipc_IPDLParamTraits_h
+#define mozilla_ipc_IPDLParamTraits_h
+
+#include "chrome/common/ipc_message_utils.h"
+#include "ipc/IPCMessageUtilsSpecializations.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Variant.h"
+
+#include "nsTArray.h"
+
+#include <type_traits>
+
+namespace mozilla {
+namespace ipc {
+
+class IProtocol;
+
+//
+// IPDLParamTraits was an extended version of ParamTraits. Unlike ParamTraits,
+// IPDLParamTraits passes an additional IProtocol* argument to the
+// write and read methods.
+//
+// Previously this was required for serializing and deserializing types which
+// require knowledge of which protocol they're being sent over, however the
+// actor is now available through `IPC::Message{Writer,Reader}::GetActor()` so
+// the extra argument is no longer necessary. Please use `IPC::ParamTraits` in
+// the future.
+//
+// Types which implement IPDLParamTraits are also supported by ParamTraits.
+//
+template <typename P>
+struct IPDLParamTraits {};
+
+//
+// WriteIPDLParam and ReadIPDLParam are like IPC::WriteParam and IPC::ReadParam,
+// however, they also accept a redundant extra actor argument.
+//
+// NOTE: WriteIPDLParam takes a universal reference, so that it can support
+// whatever reference type is supported by the underlying ParamTraits::Write
+// implementation.
+//
+template <typename P>
+static MOZ_NEVER_INLINE void WriteIPDLParam(IPC::MessageWriter* aWriter,
+                                            IProtocol* aActor, P&& aParam) {
+  MOZ_ASSERT(aActor == aWriter->GetActor());
+  IPC::WriteParam(aWriter, std::forward<P>(aParam));
+}
+
+template <typename P>
+static MOZ_NEVER_INLINE bool ReadIPDLParam(IPC::MessageReader* aReader,
+                                           IProtocol* aActor, P* aResult) {
+  MOZ_ASSERT(aActor == aReader->GetActor());
+  return IPC::ReadParam(aReader, aResult);
+}
+
+}  // namespace ipc
+}  // namespace mozilla
+
+#endif  // defined(mozilla_ipc_IPDLParamTraits_h)