some analyzer fixes for compiler

pkg/compiler/lib/src/serialization/modelz.dart

Index: pkg/compiler/lib/src/serialization/modelz.dart
diff --git a/pkg/compiler/lib/src/serialization/modelz.dart b/pkg/compiler/lib/src/serialization/modelz.dart
index c31ee4af34453b02aca007908edcfc8a73862ca8..23153bf5cf2050ef1146d2c907cc4a7b25dd1eed 100644
--- a/pkg/compiler/lib/src/serialization/modelz.dart
+++ b/pkg/compiler/lib/src/serialization/modelz.dart
@@ -12,8 +12,6 @@ library dart2js.serialization.modelz;
 import '../common.dart';
 import '../common/resolution.dart' show
     Resolution;
-import '../compiler.dart'
-    show Compiler;
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
 import '../core_types.dart';
@@ -96,9 +94,6 @@ abstract class ElementZ extends Element with ElementCommon {
   String get fixedBackendName => _unsupported('fixedBackendName');
 
   @override
-  bool get hasFixedBackendName => _unsupported('hasFixedBackendName');
-
-  @override
   LibraryElement get implementationLibrary => library;
 
   @override
@@ -132,15 +127,6 @@ abstract class ElementZ extends Element with ElementCommon {
   bool get isMixinApplication => false;
 
   @override
-  bool get isNative => false;
-
-  @override
-  bool get isJsInterop => false;
-
-  @override
-  String get jsInteropName => null;
-
-  @override
   bool get isOperator => false;
 
   @override
@@ -375,7 +361,6 @@ class LibraryElementZ extends DeserializedElementZ
   List<ExportElement> _exports;
   ListedContainer _exportsMap;
   ListedContainer _importsMap;
-  Map<LibraryTag, LibraryElement> _libraryDependencies;
 
   LibraryElementZ(ObjectDecoder decoder)
       : super(decoder);
@@ -463,9 +448,6 @@ class LibraryElementZ extends DeserializedElementZ
   }
 
   @override
-  bool get canUseNative => false;
-
-  @override
   Element findExported(String elementName) => _unsupported('findExported');
 
   void _ensureImports() {
@@ -893,9 +875,6 @@ class ClassElementZ extends DeserializedElementZ
   }
 
   @override
-  String get nativeTagInfo => _unsupported('nativeTagInfo');
-
-  @override
   void reverseBackendMembers() => _unsupported('reverseBackendMembers');
 
   @override