Step two of optionally sending messages to/from message ports as base::Value.

content/common/message_port_messages.h

Index: content/common/message_port_messages.h
diff --git a/content/common/message_port_messages.h b/content/common/message_port_messages.h
index be748a87ab014747282dc86ba1acae607a11843a..d2c6fb8e8a6936a1fa2d38876f9dbf67ea04e7ed 100644
--- a/content/common/message_port_messages.h
+++ b/content/common/message_port_messages.h
@@ -26,7 +26,8 @@
 #ifndef CONTENT_COMMON_MESSAGE_PORT_MESSAGES_H_
 #define CONTENT_COMMON_MESSAGE_PORT_MESSAGES_H_
 
-typedef std::pair<content::MessagePortMessage, std::vector<int>> QueuedMessage;
+typedef std::pair<content::MessagePortMessage,
+                  std::vector<content::TransferredMessagePort>> QueuedMessage;
 
 #endif  // CONTENT_COMMON_MESSAGE_PORT_MESSAGES_H_
 
@@ -35,15 +36,21 @@ IPC_STRUCT_TRAITS_BEGIN(content::MessagePortMessage)
   IPC_STRUCT_TRAITS_MEMBER(message_as_value)
 IPC_STRUCT_TRAITS_END()
 
+IPC_STRUCT_TRAITS_BEGIN(content::TransferredMessagePort)
+  IPC_STRUCT_TRAITS_MEMBER(id)
+  IPC_STRUCT_TRAITS_MEMBER(send_messages_as_values)
+IPC_STRUCT_TRAITS_END()
+
 //-----------------------------------------------------------------------------
 // MessagePort messages
 // These are messages sent from the browser to child processes.
 
 // Sends a message to a message port.
-IPC_MESSAGE_ROUTED3(MessagePortMsg_Message,
-                    content::MessagePortMessage /* message */,
-                    std::vector<int> /* sent_message_port_ids */,
-                    std::vector<int> /* new_routing_ids */)
+IPC_MESSAGE_ROUTED3(
+    MessagePortMsg_Message,
+    content::MessagePortMessage /* message */,
+    std::vector<content::TransferredMessagePort> /* sent_message_ports */,
+    std::vector<int> /* new_routing_ids */)
 
 // Tells the Message Port Channel object that there are no more in-flight
 // messages arriving.
@@ -66,10 +73,11 @@ IPC_MESSAGE_CONTROL1(MessagePortHostMsg_DestroyMessagePort,
 
 // Sends a message to a message port.  Optionally sends a message port as
 // as well if sent_message_port_id != MSG_ROUTING_NONE.
-IPC_MESSAGE_CONTROL3(MessagePortHostMsg_PostMessage,
-                     int /* sender_message_port_id */,
-                     content::MessagePortMessage /* message */,
-                     std::vector<int> /* sent_message_port_ids */)
+IPC_MESSAGE_CONTROL3(
+    MessagePortHostMsg_PostMessage,
+    int /* sender_message_port_id */,
+    content::MessagePortMessage /* message */,
+    std::vector<content::TransferredMessagePort> /* sent_message_ports */)
 
 // Causes messages sent to the remote port to be delivered to this local port.
 IPC_MESSAGE_CONTROL2(MessagePortHostMsg_Entangle,