Use JS backend in serialization_analysis_test

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 cbc297cf4cc364497475c455b80ddf74300db849..067c5703a5acac64e862f7087604e8291a9b5fe0 100644
--- a/pkg/compiler/lib/src/serialization/modelz.dart
+++ b/pkg/compiler/lib/src/serialization/modelz.dart
@@ -80,9 +80,6 @@ abstract class ElementZ extends Element with ElementCommon {
   }
 
   @override
-  ClassElement get contextClass => _unsupported('contextClass');
-
-  @override
   ClassElement get enclosingClass => null;
 
   @override
@@ -530,6 +527,9 @@ class CompilationUnitElementZ extends DeserializedElementZ
   CompilationUnitElement get compilationUnit => this;
 
   @override
+  Element get enclosingElement => library;
+
+  @override
   accept(ElementVisitor visitor, arg) {
     return visitor.visitCompilationUnitElement(this, arg);
   }
@@ -723,13 +723,16 @@ abstract class ParametersMixin
 abstract class FunctionTypedElementMixin
     implements FunctionElement, DeserializedElementZ {
   @override
-  AsyncMarker get asyncMarker => _unsupported('');
+  AsyncMarker get asyncMarker => _unsupported('asyncMarker');
 
   @override
-  bool get isExternal => _unsupported('');
+  FunctionElement asFunctionElement() => this;
 
   @override
-  FunctionElement asFunctionElement() => this;
+  bool get isExternal {
+    return _decoder.getBool(
+        Key.IS_EXTERNAL, isOptional: true, defaultValue: false);
+  }
 }
 
 class ClassElementZ extends DeserializedElementZ
@@ -854,7 +857,8 @@ class ClassElementZ extends DeserializedElementZ
 
   @override
   bool get isUnnamedMixinApplication {
-    return _unsupported('isUnnamedMixinApplication');
+    return _decoder.getBool(Key.IS_UNNAMED_MIXIN_APPLICATION,
+        isOptional: true, defaultValue: false);
   }
 
   @override
@@ -883,6 +887,25 @@ class ClassElementZ extends DeserializedElementZ
   }
 }
 
+
+class EnumClassElementZ extends ClassElementZ implements EnumClassElement {
+  List<FieldElement> _enumValues;
+
+  EnumClassElementZ(ObjectDecoder decoder)
+      : super(decoder);
+
+  @override
+  bool get isEnumClass => true;
+
+  @override
+  List<FieldElement> get enumValues {
+    if (_enumValues == null) {
+      _enumValues = _decoder.getElements(Key.FIELDS);
+    }
+    return _enumValues;
+  }
+}
+
 abstract class ConstructorElementZ extends DeserializedElementZ
     with AnalyzableElementMixin,
          AstElementMixin,
@@ -952,6 +975,11 @@ abstract class ConstructorElementZ extends DeserializedElementZ
   }
 
   @override
+  bool get isEffectiveTargetMalformed {
+    return _unsupported('isEffectiveTargetMalformed');
+  }
+
+  @override
   bool get isRedirectingFactory => _unsupported('isRedirectingFactory');
 
   @override