ENYO-1619: fix FormData constructor error on Android Chrome by guardi…

…ng code that uses native version with constructor check.

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@palm.com)

source/ajax/formdata.js

@@ -19,9 +19,17 @@ _enyo.FormData_ is inspired by
  */
 (function(w) {
 	if (w.FormData) {
-		enyo.FormData = w.FormData;
-		enyo.Blob = w.Blob;
-		return;
+		try {
+			var t1 = new w.FormData();
+			var t2 = new w.Blob();
+			// Android Chrome 18 will throw an error trying to create these
+			enyo.FormData = w.FormData;
+			enyo.Blob = w.Blob;
+			return;
+		}
+		catch (e) {
+			// ignore error and fall through to fake FormData code
+		}
 	}
 	function FormData() {
 		this.fake = true;