[gjs] Lang.bind: Use Function.bind() if we're not currying

[Colin Walters <walters src gnome org>]

commit 9046d4496ca5d54b34352100fa3a4e8e4461df5a
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Thu Jun 30 15:03:49 2011 -0400

    Lang.bind: Use Function.bind() if we're not currying
    
    The standard Function.bind() works, but doesn't support passing
    additional arguments.

 modules/lang.js |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/modules/lang.js b/modules/lang.js
index 018928e..5642a01 100644
--- a/modules/lang.js
+++ b/modules/lang.js
@@ -89,9 +89,6 @@ function removeNullProperties(obj) {
  * @type: function
  */
 function bind(obj, callback) {
-    let me = obj;
-    let bindArguments = Array.prototype.slice.call(arguments, 2);
-
     if (typeof(obj) != 'object') {
         throw new Error(
             "first argument to Lang.bind() must be an object, not " +
@@ -104,6 +101,12 @@ function bind(obj, callback) {
                 typeof(callback));
     }
 
+    if (callback.bind && arguments.length == 2) // ECMAScript 5 (but only if not passing any bindArguments)
+	return callback.bind(obj);
+
+    let me = obj;
+    let bindArguments = Array.prototype.slice.call(arguments, 2);
+
     return function() {
         let args = Array.prototype.slice.call(arguments);
         args = args.concat(bindArguments);