Big merge from experimental to bleeding edge.

sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart

Index: sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
diff --git a/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart b/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
index cede225be99a109917dbbcaa04c9047e58434ebd..8614d9d6df1619ceb7c322a5acc65f33fb01a419 100644
--- a/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
+++ b/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
@@ -53,14 +53,14 @@ LibraryMirror findLibrary(MemberMirror member) {
   throw new Exception('Unexpected owner: ${owner}');
 }
 
-class HierarchyIterable implements Iterable<ClassMirror> {
+class HierarchyIterable extends Iterable<ClassMirror> {
   final bool includeType;
   final ClassMirror type;
 
   HierarchyIterable(this.type, {bool includeType})
       : this.includeType = includeType;
 
-  Iterator<ClassMirror> iterator() =>
+  Iterator<ClassMirror> get iterator =>
       new HierarchyIterator(type, includeType: includeType);
 }
 
@@ -68,7 +68,7 @@ class HierarchyIterable implements Iterable<ClassMirror> {
  * [HierarchyIterator] iterates through the class hierarchy of the provided
  * type.
  *
- * First is the superclass relation is traversed, skipping [Object], next the
+ * First the superclass relation is traversed, skipping [Object], next the
  * superinterface relation and finally is [Object] visited. The supertypes are
  * visited in breadth first order and a superinterface is visited more than once
  * if implemented through multiple supertypes.
@@ -76,6 +76,7 @@ class HierarchyIterable implements Iterable<ClassMirror> {
 class HierarchyIterator implements Iterator<ClassMirror> {
   final Queue<ClassMirror> queue = new Queue<ClassMirror>();
   ClassMirror object;
+  ClassMirror _current;
 
   HierarchyIterator(ClassMirror type, {bool includeType}) {
     if (includeType) {
@@ -97,19 +98,18 @@ class HierarchyIterator implements Iterator<ClassMirror> {
     return type;
   }
 
-  ClassMirror next() {
-    ClassMirror type;
+  ClassMirror get current => _current;
+
+  bool moveNext() {
+    _current = null;
     if (queue.isEmpty) {
-      if (object == null) {
-        throw new StateError("No more elements");
-      }
-      type = object;
+      if (object == null) return false;
+      _current = object;
       object = null;
-      return type;
+      return true;
     } else {
-      return push(queue.removeFirst());
+      _current = push(queue.removeFirst());
+      return true;
     }
   }
-
-  bool get hasNext => !queue.isEmpty || object != null;
 }