Fix PresenterClass by adding a _listener field

Change-Id: I22578bba4d66d032f67ceec3e7232de13be4f175
diff --git a/tools/aidl/generate_java_rpc.cpp b/tools/aidl/generate_java_rpc.cpp
index d705c79..bcd4b76 100644
--- a/tools/aidl/generate_java_rpc.cpp
+++ b/tools/aidl/generate_java_rpc.cpp
@@ -351,6 +351,7 @@
     this->extends = PRESENTER_BASE_TYPE;
 
     this->_listener = new Variable(listenerType, "_listener");
+    this->elements.push_back(new Field(PRIVATE, this->_listener));
 
     // methods
     generate_ctor();
@@ -957,4 +958,3 @@
 
     return proxy;
 }
-