Reduce usage of .enclosingElement to get enclosing class.

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index 7aba3c44accefc88a226b09e8344a2dba8bc4830..ca7c6f2b3dc0816f83dae501ac6956a952cd9cfe 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -173,9 +173,8 @@ class SsaBuilderTask extends CompilerTask {
       graph.calledInLoop = inLoop;
       if (compiler.tracer.enabled) {
         String name;
-        if (element.enclosingElement !== null &&
-            element.enclosingElement.kind == ElementKind.CLASS) {
-          String className = element.enclosingElement.name.slowToString();
+        if (element.isMember()) {
+          String className = element.getEnclosingClass().name.slowToString();
           String memberName = element.name.slowToString();
           name = "$className.$memberName";
           if (element.kind == ElementKind.GENERATIVE_CONSTRUCTOR_BODY) {
@@ -193,7 +192,7 @@ class SsaBuilderTask extends CompilerTask {
 
   HGraph compileConstructor(SsaBuilder builder, WorkItem work) {
     // The body of the constructor will be generated in a separate function.
-    final ClassElement classElement = work.element.enclosingElement;
+    final ClassElement classElement = work.element.getEnclosingClass();
     return builder.buildFactory(classElement, work.element);
   }
 }
@@ -339,7 +338,7 @@ class LocalsHandler {
       // Once closures have been mapped to classes their instance members might
       // not have any thisElement if the closure was created inside a static
       // context.
-      ClassElement cls = function.enclosingElement;
+      ClassElement cls = function.getEnclosingClass();
       Type type = cls.computeType(builder.compiler);
       HInstruction thisInstruction = new HThis(new HBoundedType.nonNull(type));
       builder.add(thisInstruction);
@@ -368,7 +367,7 @@ class LocalsHandler {
     if (isAccessedDirectly(element)) return false;
     Element redirectTarget = redirectionMapping[element];
     if (redirectTarget == null) return false;
-    if (redirectTarget.enclosingElement.kind == ElementKind.CLASS) {
+    if (redirectTarget.isMember()) {
       assert(redirectTarget is ClosureFieldElement);
       return true;
     }
@@ -432,7 +431,7 @@ class LocalsHandler {
       if (cachedTypeOfThis === null) {
         assert(closureData.isClosure());
         Element element = closureData.thisElement;
-        ClassElement cls = element.enclosingElement.enclosingElement;
+        ClassElement cls = element.enclosingElement.getEnclosingClass();
         Type type = cls.computeType(builder.compiler);
         cachedTypeOfThis = new HBoundedType.nonNull(type);
       }
@@ -861,7 +860,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
       NodeList statements = node.body.asBlock().statements;
       if (statements.isEmpty()) return null;
     }
-    ClassElement classElement = constructor.enclosingElement;
+    ClassElement classElement = constructor.getEnclosingClass();
     ConstructorBodyElement bodyElement;
     for (Link<Element> backendMembers = classElement.backendMembers;
          !backendMembers.isEmpty();
@@ -969,7 +968,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
     if (!foundSuperOrRedirect) {
       // No super initializer found. Try to find the default constructor if
       // the class is not Object.
-      ClassElement enclosingClass = constructor.enclosingElement;
+      ClassElement enclosingClass = constructor.getEnclosingClass();
       ClassElement superClass = enclosingClass.superclass;
       if (enclosingClass != compiler.objectClass) {
         assert(superClass !== null);
@@ -2263,14 +2262,14 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
   visitNewSend(Send node) {
     computeType(element) {
       Element originalElement = elements[node];
-      if (originalElement.enclosingElement === compiler.listClass) {
+      if (originalElement.getEnclosingClass() === compiler.listClass) {
         if (node.arguments.isEmpty()) {
           return HType.EXTENDABLE_ARRAY;
         } else {
           return HType.MUTABLE_ARRAY;
         }
       } else if (element.isGenerativeConstructor()) {
-        ClassElement cls = element.enclosingElement;
+        ClassElement cls = element.getEnclosingClass();
         return new HBoundedType.exact(cls.type);
       } else {
         return HType.UNKNOWN;