Reduce usage of .enclosingElement to get enclosing class.

lib/compiler/implementation/universe.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class Universe {
   Map<Element, CodeBuffer> generatedCode;
   Map<Element, CodeBuffer> generatedBailoutCode;
   final Set<ClassElement> instantiatedClasses;
   final Set<SourceString> instantiatedClassInstanceFields;
   final Set<FunctionElement> staticFunctionsNeedingGetter;
@@ skipping 286 matching lines @@
     : super(selector.kind,
             selector.argumentCount,
             selector.namedArguments);
 
   /**
    * Check if [element] will be the one used at runtime when being
    * invoked on an instance of [cls].
    */
   bool hasElementIn(ClassElement cls, Element element) {
     Element resolved = cls.lookupMember(element.name);
-    if (resolved === element) return  true;
+    if (resolved === element) return true;
     if (resolved === null) return false;
     if (resolved.kind === ElementKind.ABSTRACT_FIELD) {
       AbstractFieldElement field = resolved;
       if (element === field.getter || element === field.setter) {
         return true;
       } else {
-        ClassElement otherCls = field.enclosingElement;
+        ClassElement otherCls = field.getEnclosingClass();
         // We have not found a match, but another class higher in the
         // hierarchy may define the getter or the setter.
         return hasElementIn(otherCls.superclass, element);
       }
     }
     return false;
   }
 
   bool applies(Element element, Compiler compiler) {
-    if (!element.enclosingElement.isClass()) return false;
+    if (!element.isMember()) return false;
 
     // A closure can be called through any typed selector:
     // class A {
     //   get foo() => () => 42;
     //   bar() => foo(); // The call to 'foo' is a typed selector.
     // }
-    ClassElement other = element.enclosingElement;
+    ClassElement other = element.getEnclosingClass();
     if (other.superclass === compiler.closureClass) {
       return super.applies(element, compiler);
     }
 
     ClassElement self = receiverType.element;
     // TODO(ngeoffray): tree-shake on interfaces.
     if (self.isInterface() || other.isSubclassOf(self)) {
       return super.applies(element, compiler);
     }
 
     if (!self.isInterface() && self.isSubclassOf(other)) {
       // Resolve an invocation of [element.name] on [self]. If it
       // is found, this selector is a candidate.
       return hasElementIn(self, element) && super.applies(element, compiler);
     }
 
     return false;
   }
 
   bool operator ==(other) {
     if (other is !TypedSelector) return false;
     if (other.receiverType !== receiverType) return false;
     return super == other;
   }
 }