Expose errorCode in JS API (#845)

JavaScript API library didn't expose the ResultOrErrorCode's error code
value. The "errorCode" property wasn't marked as exported, hence it was
unaccessible after minification.

This commit fixes this by exporting a new "getErrorCode" method instead.
This fixes #793.

third_party/pcsc-lite/naclport/js_client/src/api.js

@@ -2147,6 +2147,17 @@ goog.exportProperty(
     API.ResultOrErrorCode.prototype, 'getBase',
     API.ResultOrErrorCode.prototype.getBase);
 
+/**
+ * @return {!API.ERROR_CODE}
+ */
+API.ResultOrErrorCode.prototype.getErrorCode = function() {
+  return this.errorCode;
+};
+
+goog.exportProperty(
+    API.ResultOrErrorCode.prototype, 'getErrorCode',
+    API.ResultOrErrorCode.prototype.getErrorCode);
+
 /**
  * @return {boolean}
  */