Refactor prefs.js for MD-Settings

chrome/browser/resources/settings/checkbox/checkbox.js

Index: chrome/browser/resources/settings/checkbox/checkbox.js
diff --git a/chrome/browser/resources/settings/checkbox/checkbox.js b/chrome/browser/resources/settings/checkbox/checkbox.js
index d4bdeb4fc378da44e7864b61c7b6c070f9f80383..d6514fc9bd04a060be5c2365a3db3642a7981283 100644
--- a/chrome/browser/resources/settings/checkbox/checkbox.js
+++ b/chrome/browser/resources/settings/checkbox/checkbox.js
@@ -68,7 +68,7 @@ Polymer({
   /** @private */
   checkedChanged_: function() {
     if (this.pref) {
-      this.pref.value = this.getNewValue_(this.checked);
+      this.set('pref.value', this.getNewValue_(this.checked));

[Dan Beam, 2015/08/26 16:51:33]

what's the functional difference?  this notifies observers?

[stevenjb, 2015/08/26 17:32:18]

Correct.
https://www.polymer-project.org/1.0/docs/devguide/properties.html#observing-p...

[michaelpg, 2015/08/26 23:32:15]

To expand on steven's answer:

Polymer doesn't use Object.observe. Top-level element properties are actually
setters which use the prototype's "properties" object. Beyond the top level,
Polymer doesn't own the data, so it only knows of a change if a change event is
fired.

Data binding fires these events automatically. When we manually change
sub-properties, we have to trigger an event using notifyPath or set (a
convenience function combining "operator=" and notifyPath).

     }
   },