Resolve AidlTypeSpecifier with AidlDefinedType

After resolving, AidlTypeSpecifier has the reference
to associated AidlDefinedType.

Bug: n/a
Test: aidl_integration_test
Change-Id: I3520a60f38395ed3a2eab365ead4484df7ec4907
diff --git a/aidl_language.h b/aidl_language.h
index 7bc249b..53616b7 100644
--- a/aidl_language.h
+++ b/aidl_language.h
@@ -314,6 +314,8 @@
   bool LanguageSpecificCheckValid(const AidlTypenames& typenames, Options::Language lang) const;
   const AidlNode& AsAidlNode() const override { return *this; }
 
+  const AidlDefinedType* GetDefinedType() const;
+
  private:
   AidlTypeSpecifier(const AidlTypeSpecifier&) = default;
 
@@ -322,6 +324,7 @@
   bool is_array_;
   string comments_;
   vector<string> split_name_;
+  const AidlDefinedType* defined_type_;  // set when Resolve() for defined types
   mutable shared_ptr<AidlTypeSpecifier> array_base_;
 };