Generalize DeclarationBuilder.resolveTypes.

pkg/front_end/lib/src/fasta/source/source_library_builder.dart

Index: pkg/front_end/lib/src/fasta/source/source_library_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
index 9174707dbd3bf35e239e8a22d70b57be20fc994c..76e47edbb7cce4d2bf2273afb10282c33e7671c3 100644
--- a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
@@ -88,11 +88,6 @@ abstract class SourceLibraryBuilder<T extends TypeBuilder, R>
     return currentDeclaration.members;
   }
 
-  List<T> get declarationTypes {
-    assert(currentDeclaration.parent == libraryDeclaration);
-    return currentDeclaration.types;
-  }
-
   T addNamedType(String name, List<T> arguments, int charOffset);
 
   T addMixinApplication(T supertype, List<T> mixins, int charOffset);