Add the feature to retain the user gesture in the extension callback

extensions/common/extension_messages.h

Index: extensions/common/extension_messages.h
===================================================================
--- extensions/common/extension_messages.h	(revision 262146)
+++ extensions/common/extension_messages.h	(working copy)
@@ -296,11 +296,12 @@
 // The browser sends this message in response to all extension api calls. The
 // response data (if any) is one of the base::Value subclasses, wrapped as the
 // first element in a ListValue.
-IPC_MESSAGE_ROUTED4(ExtensionMsg_Response,
+IPC_MESSAGE_ROUTED5(ExtensionMsg_Response,
                     int /* request_id */,
                     bool /* success */,
                     base::ListValue /* response wrapper (see comment above) */,
-                    std::string /* error */)
+                    std::string /* error */,
+                    bool /* whether the response callback has user gesture */)
 
 // This message is optionally routed.  If used as a control message, it will
 // call a javascript function |function_name| from module |module_name| in