Visit meta methods as well.

getInterfaceVersion/getInterfaceHash are added dynamically. AidlVisitor
now visits these meta methods as well.

AidlVisitor can skip these methods by looking up IsUserDefined().

Bug: 201584220
Test: m
Change-Id: I43301eaf15f3b3d8368b309a2d8e351e1685b8d2
diff --git a/aidl_language.h b/aidl_language.h
index 33f039e..749eed2 100644
--- a/aidl_language.h
+++ b/aidl_language.h
@@ -960,7 +960,10 @@
     return constants_;
   }
   const std::vector<std::unique_ptr<AidlMethod>>& GetMethods() const { return methods_; }
-  void AddMethod(std::unique_ptr<AidlMethod> method) { methods_.push_back(std::move(method)); }
+  void AddMethod(std::unique_ptr<AidlMethod> method) {
+    members_.push_back(method.get());
+    methods_.push_back(std::move(method));
+  }
   const std::vector<const AidlMember*>& GetMembers() const { return members_; }
   void TraverseChildren(std::function<void(const AidlNode&)> traverse) const override {
     AidlAnnotatable::TraverseChildren(traverse);