[json & uri] cleanup === and !==

lib/uri/uri.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.
 
 #library('dart:uri');
 
 #import('dart:math');
 #import('dart:utf');
 
 #source('encode_decode.dart');
@@ skipping 30 matching lines @@
                             this.port: 0,
                             this.path: "",
                             this.query: "",
                             this.fragment: ""});
 
   Uri(String uri) : this.fromString(uri);
 
   static String _emptyIfNull(String val) => val != null ? val : '';
 
   static int _parseIntOrZero(String val) {
-    if (val !== null && val != '') {
+    if (val != null && val != '') {
       return int.parse(val);
     } else {
       return 0;
     }
   }
 
   // NOTE: This code was ported from: closure-library/closure/goog/uri/utils.js
   static const RegExp _splitRe = const RegExp(
       '^'
       '(?:'
@@ skipping 148 matching lines @@
     }
     return sb.toString();
   }
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     _addIfNonEmpty(sb, scheme, scheme, ':');
     if (hasAuthority() || (scheme == "file")) {
       sb.add("//");
       _addIfNonEmpty(sb, userInfo, userInfo, "@");
-      sb.add(domain === null ? "null" : domain);
+      sb.add(domain == null ? "null" : domain);
       if (port != 0) {
         sb.add(":");
         sb.add(port.toString());
       }
     }
-    sb.add(path === null ? "null" : path);
+    sb.add(path == null ? "null" : path);
     _addIfNonEmpty(sb, query, "?", query);
     _addIfNonEmpty(sb, fragment, "#", fragment);
     return sb.toString();
   }
 
   static void _addIfNonEmpty(StringBuffer sb, String test,
                              String first, String second) {
     if ("" != test) {
-      sb.add(first === null ? "null" : first);
-      sb.add(second === null ? "null" : second);
+      sb.add(first == null ? "null" : first);
+      sb.add(second == null ? "null" : second);
     }
   }
 }