union support for NDK backend

Generated class for AIDL union for NDK backend is similar to the one for
C++ backend. Differences are
- not inheriting Parcelable, but has similar read/write methods
- not having comparison operators.

Bug: 150948558
Bug: 170784707
Test: aidl_unittests / aidl_integration_test
Test: CtsNdkBinderTestCases
Change-Id: Ib7f9265d7664ae98b9edd4a40d50351180c9a4d2
diff --git a/aidl_to_cpp_common.h b/aidl_to_cpp_common.h
index f49edb0..3c6996e 100644
--- a/aidl_to_cpp_common.h
+++ b/aidl_to_cpp_common.h
@@ -73,7 +73,7 @@
 
 std::string GenerateEnumValues(const AidlEnumDeclaration& enum_decl,
                                const std::vector<std::string>& enclosing_namespaces_of_enum_decl);
-std::string TemplateDecl(const AidlStructuredParcelable& defined_type);
+std::string TemplateDecl(const AidlParcelable& defined_type);
 
 void GenerateParcelableComparisonOperators(CodeWriter& out, const AidlParcelable& parcelable);