FBTF: Allow forward declaration of classes passed to sync IPC messages.

ipc/ipc_message_utils_impl.h

Index: ipc/ipc_message_utils_impl.h
diff --git a/ipc/ipc_message_utils_impl.h b/ipc/ipc_message_utils_impl.h
index 91b4ac9e7ce22c0cd90939d5b623aec923960e66..b3a3a7b70fe3fa579296409d91a30904d1156a7b 100644
--- a/ipc/ipc_message_utils_impl.h
+++ b/ipc/ipc_message_utils_impl.h
@@ -18,19 +18,26 @@ MessageWithTuple<ParamType>::MessageWithTuple(
   WriteParam(this, p);
 }
 
-template <class ParamType>
-bool MessageWithTuple<ParamType>::Read(const Message* msg, Param* p) {
-  void* iter = NULL;
-  if (ReadParam(msg, &iter, p))
-    return true;
-  NOTREACHED() << "Error deserializing message " << msg->type();
-  return false;
-}
+// TODO(erg): Migrate the Read() methods here when I figure out the linkage
+// problems that broke the release build.
 
 // We can't migrate the template for Log() to MessageWithTuple, because each
 // subclass needs to have Log() to call Read(), which instantiates the above
 // template.
 
+template <class SendParamType, class ReplyParamType>
+MessageWithReply<SendParamType, ReplyParamType>::MessageWithReply(
+    int32 routing_id, uint32 type,
+    const RefSendParam& send,
+    const ReplyParam& reply)
+    : SyncMessage(routing_id, type, PRIORITY_NORMAL,
+                  new ParamDeserializer<ReplyParam>(reply)) {
+  WriteParam(this, send);
+}
+
+// TODO(erg): Migrate ReadSendParam()/ReadReplyParam() here when we can force
+// the visibility/linkage.
+
 }  // namespace IPC
 
 #endif  // IPC_IPC_MESSAGE_UTILS_IMPL_H_