Remove NullPointerException.

sdk/lib/core/map.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.
 
 /**
  * A [Map] is an associative container, mapping a key to a value.
  * Null values are supported, but null keys are not.
  */
 abstract class Map<K, V> {
   /**
@@ skipping 171 matching lines @@
 
   static int _firstProbe(int hashCode, int length) {
     return hashCode & (length - 1);
   }
 
   static int _nextProbe(int currentProbe, int numberOfProbes, int length) {
     return (currentProbe + numberOfProbes) & (length - 1);
   }
 
   int _probeForAdding(K key) {
-    if (key == null) throw const NullPointerException();
+    if (key == null) throw new ArgumentError(null);
     int hash = _firstProbe(key.hashCode, _keys.length);
     int numberOfProbes = 1;
     int initialHash = hash;
     // insertionIndex points to a slot where a key was deleted.
     int insertionIndex = -1;
     while (true) {
       // [existingKey] can be either of type [K] or [_DeletedKeySentinel].
       Object existingKey = _keys[hash];
       if (existingKey == null) {
         // We are sure the key is not already in the set.
@@ skipping 14 matching lines @@
       }
 
       // We did not find an insertion slot. Look at the next one.
       hash = _nextProbe(hash, numberOfProbes++, _keys.length);
       // _ensureCapacity has guaranteed the following cannot happen.
       // assert(hash != initialHash);
     }
   }
 
   int _probeForLookup(K key) {
-    if (key == null) throw const NullPointerException();
+    if (key == null) throw new ArgumentError(null);
     int hash = _firstProbe(key.hashCode, _keys.length);
     int numberOfProbes = 1;
     int initialHash = hash;
     while (true) {
       // [existingKey] can be either of type [K] or [_DeletedKeySentinel].
       Object existingKey = _keys[hash];
       // If the slot does not contain anything (in particular, it does not
       // contain a deleted key), we know the key is not in the map.
       if (existingKey == null) return -1;
       // The key is in the map, return its index.
@@ skipping 280 matching lines @@
 
   void clear() {
     _map.clear();
     _list.clear();
   }
 
   String toString() {
     return Maps.mapToString(this);
   }
 }