Implement override checks for methods.

pkg/front_end/lib/src/fasta/analyzer/analyzer_loader.dart

Index: pkg/front_end/lib/src/fasta/analyzer/analyzer_loader.dart
diff --git a/pkg/front_end/lib/src/fasta/analyzer/analyzer_loader.dart b/pkg/front_end/lib/src/fasta/analyzer/analyzer_loader.dart
index 6cacc9e65b835e57894ff47caeb448a0f71c8946..979ba948072c72c32707ac6a21b4bb2cb58c3cd1 100644
--- a/pkg/front_end/lib/src/fasta/analyzer/analyzer_loader.dart
+++ b/pkg/front_end/lib/src/fasta/analyzer/analyzer_loader.dart
@@ -10,6 +10,8 @@ import '../builder/builder.dart' show LibraryBuilder;
 
 import '../target_implementation.dart' show TargetImplementation;
 
+import '../source/source_class_builder.dart' show SourceClassBuilder;
+
 import '../source/source_loader.dart' show SourceLoader;
 
 import 'element_store.dart' show ElementStore;
@@ -31,4 +33,9 @@ class AnalyzerLoader<L> extends SourceLoader<L> {
   AnalyzerDietListener createDietListener(LibraryBuilder library) {
     return new AnalyzerDietListener(library, elementStore);
   }
+
+  @override
+  void checkOverrides(List<SourceClassBuilder> sourceClasses) {
+    // Not implemented yet. Requires [hierarchy].
+  }
 }