Clean up (most) uses of Array. Still more to come in the VM corelib code base.

corelib/src/implementation/hash_map_set.dart

 // Copyright (c) 2011, 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.
 
 // Hash map implementation with open addressing and quadratic probing.
 class HashMapImplementation<K extends Hashable, V> implements HashMap<K, V> {
 
-  // The [keys_] list contains the keys inserted in the map.
-  // The [keys_] list must be a raw list because it
-  // will contain both elements of type K, and the [deletedKey_] of type
+  // The [_keys] list contains the keys inserted in the map.
+  // The [_keys] list must be a raw list because it
+  // will contain both elements of type K, and the [_deletedKey] of type
   // Object.
-  // The alternative of declaring the [keys_] list as of type Object
+  // The alternative of declaring the [_keys] list as of type Object
   // does not work, because the HashSetIterator constructor would fail:
-  //  HashSetIterator(HashSet<E> set_)
+  //  HashSetIterator(HashSet<E> set)
   //    : _nextValidIndex = -1,
   //      _entries = set_._backingMap._keys {
   //    _advance();
   //  }
   // With K being type int, for example, it would fail because
-  // ObjectArray<Object> is not assignable to type List<int> of entries_.
+  // List<Object> is not assignable to type List<int> of entries.
   List _keys;
 
-  // The values_ inserted in the map. For a filled entry index in this
+  // The values inserted in the map. For a filled entry index in this
   // list, there is always the corresponding key in the [keys_] list
   // at the same entry index.
   List<V> _values;
 
   // The load limit is the number of entries we allow until we double
   // the size of the lists.
   int _loadLimit;
 
   // The current number of entries in the map. Will never be greater
   // than [_loadLimit].
@@ skipping 383 matching lines @@
   }
 
   // The entries in the set. May contain null or the sentinel value.
   List<E> _entries;
 
   // The next valid index in [_entries] or the length of [entries_].
   // If it is the length of [_entries], calling [hasNext] on the
   // iterator will return false.
   int _nextValidIndex;
 }