MD Bookmarks: Update a couple of TODOs

chrome/browser/resources/md_bookmarks/store_client.js

Index: chrome/browser/resources/md_bookmarks/store_client.js
diff --git a/chrome/browser/resources/md_bookmarks/store_client.js b/chrome/browser/resources/md_bookmarks/store_client.js
index 7d1512734967740a7b2c1f51f90ab171bc17bd8a..6cea153d2f3231cbf5817df3b4a1425e45ad4a8a 100644
--- a/chrome/browser/resources/md_bookmarks/store_client.js
+++ b/chrome/browser/resources/md_bookmarks/store_client.js
@@ -49,7 +49,10 @@ cr.define('bookmarks', function() {
      * @param {function(!BookmarksPageState)} valueGetter
      */
     watch: function(localProperty, valueGetter) {
-      // TODO(tsergeant): Warn if localProperty is not a defined property.
+      if (!this.getPropertyInfo(localProperty).defined) {

[tsergeant, 2017/05/02 05:09:10]

I originally TODO'd this because I thought it would be hard to deal with
behaviors...but this nifty function does it for us.

[calamity, 2017/05/02 05:35:59]

Heh.

Polymer 2.0:
Removed APIs
- element.getPropertyInfo: This api returned unexpected information some of the
time and was rarely used.

[tsergeant, 2017/05/02 05:41:56]

😔

+        console.error(
+            'No property ' + localProperty + ' defined on ' + this.is);
+      }
       this.watches_.push({
         localProperty: localProperty,
         valueGetter: valueGetter,