Avoid CSP errors in Chrome apps by using global var detection.

Fixes #301.

Author: ljharb

es6-shim.js

@@ -144,7 +144,15 @@
   }());
 
   /*jshint evil: true */
-  var getGlobal = new Function('return this;');
+  var getGlobal = function () {
+	// the only reliable means to get the global object is
+	// `Function('return this')()`
+	// However, this causes CSP violations in Chrome apps.
+    if (typeof self !== 'undefined') { return self; }
+    if (typeof window !== 'undefined') { return window; }
+    if (typeof global !== 'undefined') { return global; }
+	throw new Error('unable to locate global object');
+  };
   /*jshint evil: false */
 
   var globals = getGlobal();