js: Add Function.prototype.bind polyfill to make PhantomJS 1.6 happy

js/test/bind-helper.js

@@ -0,0 +1,29 @@
+/*
+ * PhantomJS 1.6 does not support Function.prototype.bind, so we polyfill it.
+ *
+ * Implementation from:
+ * https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Function/bind
+ */
+if (!Function.prototype.bind) {
+  Function.prototype.bind = function (oThis) {
+    if (typeof this !== "function") {
+      // closest thing possible to the ECMAScript 5 internal IsCallable function
+      throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");
+    }
+
+    var aArgs = Array.prototype.slice.call(arguments, 1),
+        fToBind = this,
+        fNOP = function () {},
+        fBound = function () {
+          return fToBind.apply(this instanceof fNOP && oThis
+                                 ? this
+                                 : oThis,
+                               aArgs.concat(Array.prototype.slice.call(arguments)));
+        };
+
+    fNOP.prototype = this.prototype;
+    fBound.prototype = new fNOP();
+
+    return fBound;
+  };
+}