All strong mode cleaning of dart2js.

pkg/compiler/lib/src/util/maplet.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.util.maplet;
 
 import 'dart:collection' show MapBase, IterableBase;
 
 class Maplet<K, V> extends MapBase<K, V> {
   static const _MapletMarker _MARKER = const _MapletMarker();
@@ skipping 36 matching lines @@
   int get length {
     if (_extra == null) {
       return (_MARKER == _key) ? 0 : 1;
     } else if (_MARKER == _extra) {
       return _key.length;
     } else {
       return _extra;
     }
   }
 
-  bool containsKey(K key) {
+  bool containsKey(Object key) {
     if (_extra == null) {
       return _key == key;
     } else if (_MARKER == _extra) {
       return _key.containsKey(key);
     } else {
       for (int remaining = _extra, i = 0; remaining > 0 && i < CAPACITY; i++) {
         var candidate = _key[i];
         if (_MARKER == candidate) continue;
         if (candidate == key) return true;
         remaining--;
       }
       return false;
     }
   }
 
-  V operator [](K key) {
+  V operator [](Object key) {
     if (_extra == null) {
       return (_key == key) ? _value : null;
     } else if (_MARKER == _extra) {
       return _key[key];
     } else {
       for (int remaining = _extra, i = 0; remaining > 0 && i < CAPACITY; i++) {
         var candidate = _key[i];
         if (_MARKER == candidate) continue;
         if (candidate == key) return _key[i + CAPACITY];
         remaining--;
@@ skipping 75 matching lines @@
       } else {
         Map map = new Map();
         forEach((eachKey, eachValue) => map[eachKey] = eachValue);
         map[key] = value;
         _key = map;
         _extra = _MARKER;
       }
     }
   }
 
-  V remove(K key) {
+  V remove(Object key) {
     if (_extra == null) {
       if (_key != key) return null;
       _key = _MARKER;
       V result = _value;
       _value = null;
       return result;
     } else if (_MARKER == _extra) {
       return _key.remove(key);
     } else {
       for (int remaining = _extra, i = 0; remaining > 0 && i < CAPACITY; i++) {
@@ skipping 91 matching lines @@
       if (Maplet._MARKER != candidate) {
         _current = candidate;
         _remaining--;
         return true;
       }
     }
     _current = null;
     return false;
   }
 }