Revert "Add "contains" method to Collection."

runtime/lib/growable_array.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 _GrowableObjectArray<T> implements List<T> {
   factory _GrowableObjectArray._uninstantiable() {
     throw const UnsupportedOperationException(
         "GrowableObjectArray can only be allocated by the VM");
   }
 
@@ skipping 148 matching lines @@
   }
 
   void _grow(int new_length) {
     var new_data = new _ObjectArray<T>(new_length);
     for (int i = 0; i < length; i++) {
       new_data[i] = this[i];
     }
     _setData(new_data);
   }
 
-  // Collection interface.
-
-  bool contains(T element) => Collections.contains(this, element);
+  /**
+   * Collection interface.
+   */
 
   void forEach(f(T element)) {
     // TODO(srdjan): Use Collections.forEach(this, f);
     // Accessing the list directly improves DeltaBlue performance by 25%.
     for (int i = 0; i < length; i++) {
       f(this[i]);
     }
   }
 
   Collection map(f(T element)) {
@@ skipping 27 matching lines @@
 
   void sort([Comparator<T> compare = Comparable.compare]) {
     DualPivotQuicksort.sort(this, compare);
   }
 
   String toString() {
     return Collections.collectionToString(this);
   }
 
   Iterator<T> iterator() {
-    return new SequenceIterator<T>(this);
+    return new VariableSizeArrayIterator<T>(this);
   }
 }
+
+
+// Iterator for arrays with variable size.
+class VariableSizeArrayIterator<T> implements Iterator<T> {
+  VariableSizeArrayIterator(_GrowableObjectArray<T> array)
+      : _array = array,  _pos = 0 {
+  }
+
+  bool hasNext() {
+    return _array.length > _pos;
+  }
+
+  T next() {
+    if (!hasNext()) {
+      throw const NoMoreElementsException();
+    }
+    return _array[_pos++];
+  }
+
+  final _GrowableObjectArray<T> _array;
+  int _pos;
+}