Mojo JS bindings: change arrow operator in bindings.js to the old style.

mojo/public/js/bindings.js

Index: mojo/public/js/bindings.js
diff --git a/mojo/public/js/bindings.js b/mojo/public/js/bindings.js
index f7795a626fe1576caf9791fc155579e3033ed8af..83a2272fb031426ddcc58fee430ba6f806883fb4 100644
--- a/mojo/public/js/bindings.js
+++ b/mojo/public/js/bindings.js
@@ -188,8 +188,9 @@ define("mojo/public/js/bindings", [
     this.bindingId_ = bindingId;
     this.binding_ = new Binding(interfaceType, impl, requestOrHandle);
 
-    this.binding_.setConnectionErrorHandler(
-        () => this.bindingSet_.onConnectionError(bindingId));
+    this.binding_.setConnectionErrorHandler(function() {
+      this.bindingSet_.onConnectionError(bindingId);
+    }.bind(this));
   }
 
   BindingSetEntry.prototype.close = function() {