
+ dom-repeat reuses elements for the sake of efficiency, and according to [1], it’s considered an anti-pattern to do one-shot state setup by inspecting attributes/properties in ready/attached. + Move state management to be more explicit instead of one-time setup in ready(). [1] https://github.com/Polymer/polymer/issues/1713 Bug: Issue 3979 Change-Id: I5a7d2ae222223cf1ac8703cd30c66f004b606cfc