Typecheck some of ui/webui/resources/js/ with Closure compiler.

ui/webui/resources/js/template_data_externs.js

Index: ui/webui/resources/js/template_data_externs.js
diff --git a/mojo/public/java/bindings/src/org/chromium/mojo/bindings/Interface.java b/ui/webui/resources/js/template_data_externs.js
similarity index 60%
copy from mojo/public/java/bindings/src/org/chromium/mojo/bindings/Interface.java
copy to ui/webui/resources/js/template_data_externs.js
index 0b8592d52a4ecbd40ca8f57f622100302eee0ac7..d5b8fb9290617834b5dec4f927f08a3542c391b3 100644
--- a/mojo/public/java/bindings/src/org/chromium/mojo/bindings/Interface.java
+++ b/ui/webui/resources/js/template_data_externs.js
@@ -2,11 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package org.chromium.mojo.bindings;
-
 /**
- * Base class for mojo generated interfaces.
+ * @fileoverview Externs for |templateData| global.
+ * @externs
  */
-public interface Interface {
 
-}
+/** @type {!Object|undefined} */
+var templateData;