Add types for valueFromDecomposedDate

tool/input_sdk/private/js_helper.dart

 // Copyright (c) 2013, 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._js_helper;
 
 import 'dart:collection';
 
 import 'dart:_foreign_helper' show
     JS,
@@ skipping 342 matching lines @@
     match = JS('JSArray|Null', r'/(?:GMT|UTC)[+-]\d{4}/.exec(#.toString())', d);
     if (match != null) return match[0];
     return "";
   }
 
   static int getTimeZoneOffsetInMinutes(DateTime receiver) {
     // Note that JS and Dart disagree on the sign of the offset.
     return -JS('int', r'#.getTimezoneOffset()', lazyAsJsDate(receiver));
   }
 
-  static valueFromDecomposedDate(years, month, day, hours, minutes, seconds,
-                                 milliseconds, isUtc) {
+  static num valueFromDecomposedDate(int years, int month, int day, int hours,
+        int minutes, int seconds, int milliseconds, bool isUtc) {
     final int MAX_MILLISECONDS_SINCE_EPOCH = 8640000000000000;
     checkInt(years);
     checkInt(month);
     checkInt(day);
     checkInt(hours);
     checkInt(minutes);
     checkInt(seconds);
     checkInt(milliseconds);
     checkBool(isUtc);
     var jsMonth = month - 1;
-    var value;
+    num value;
     if (isUtc) {
       value = JS('num', r'Date.UTC(#, #, #, #, #, #, #)',
                  years, jsMonth, day, hours, minutes, seconds, milliseconds);
     } else {
       value = JS('num', r'new Date(#, #, #, #, #, #, #).valueOf()',
                  years, jsMonth, day, hours, minutes, seconds, milliseconds);
     }
     if (value.isNaN ||
         value < -MAX_MILLISECONDS_SINCE_EPOCH ||
         value > MAX_MILLISECONDS_SINCE_EPOCH) {
@@ skipping 478 matching lines @@
   // we have no way of telling the compiler yet, so it will generate an extra
   // layer of indirection that wraps the SyncIterator.
   _jsIterator() => JS('', '#(...#)', _generator, _args);
 
   Iterator<E> get iterator => new SyncIterator<E>(_jsIterator());
 }
 
 class BooleanConversionAssertionError extends AssertionError {
   toString() => 'Failed assertion: boolean expression must not be null';
 }