Remove =List in JS, use JSExtendableArray instead.

sdk/lib/_internal/lib/js_rti.dart

Index: sdk/lib/_internal/lib/js_rti.dart
===================================================================
--- sdk/lib/_internal/lib/js_rti.dart	(revision 24212)
+++ sdk/lib/_internal/lib/js_rti.dart	(working copy)
@@ -418,6 +418,11 @@
   return JS('int', r'#.length', array);
 }
 
+/// Returns whether [value] is a JavaScript array.

[kasperl, 2013/06/21 06:03:55]

Should we just get rid of this and inline it at the use sites?

[ngeoffray, 2013/06/24 09:47:23]

Keeping it makes the code that uses it actually nicer. The users often do things
like:

if (isJsFunction(a) || isJsArray(a)) ....

+bool isJsArray(var value) {
+  return value is JSArray;
+}
+
 /// Returns [:true:] if [o] is a JavaScript function.
 bool isJsFunction(var o) => JS('bool', r'typeof # == "function"', o);