Adding MimeHandlerView.

extensions/common/extension_messages.h

 // Copyright 2014 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.
 
 // IPC messages for extensions.
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
@@ skipping 708 matching lines @@
                     extensions::StackTrace /* stack trace */,
                     int32 /* severity level */)
 
 // Sent by the renderer to set initialization parameters of a Browser Plugin
 // that is identified by |element_instance_id|.
 IPC_MESSAGE_CONTROL4(ExtensionHostMsg_AttachGuest,
                      int /* routing_id */,
                      int /* element_instance_id */,
                      int /* guest_instance_id */,
                      base::DictionaryValue /* attach_params */)
+
+IPC_MESSAGE_CONTROL4(ExtensionHostMsg_CreateMimeHandlerViewGuest,
+                     int /* render_frame_id */,
+                     std::string /* embedder_url */,
+                     std::string /* mime_type */,
+                     int /* element_instance_id */)
+
+IPC_MESSAGE_CONTROL2(ExtensionMsg_CreateMimeHandlerViewGuestACK,
+                     int /* element_instance_id */,
+                     int /* guest_instance_id */)