[inspector_protocol] support fall through and moveable Maybe

lib/Forward_h.template

Index: lib/Forward_h.template
diff --git a/lib/Forward_h.template b/lib/Forward_h.template
index 2ad3897ba9d3e4194dc8ed8a83fffa1ed957c3d9..93de83a4bdb11b8d1f967ca58c300cfbabea2652 100644
--- a/lib/Forward_h.template
+++ b/lib/Forward_h.template
@@ -19,12 +19,14 @@ namespace {{namespace}} {
 
 template<typename T> class Array;
 class DictionaryValue;
+class DispatchResponse;
 using ErrorString = String;
 class ErrorSupport;
 class FundamentalValue;
 class ListValue;
 template<typename T> class Maybe;
 class Object;
+using Response = DispatchResponse;
 class SerializedValue;
 class StringValue;
 class UberDispatcher;