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This task is part of the effort to rework the Starter Page Template Picker for new pages. This part of the initiative will focus on caching the data as a result of the call made in #2443 and as modified by related issues.

Goals

• The data from the API should be fetched every time the picker loads for WPCOM sites.
• The UI should be updated only if there are changes as a result of the fetch.
  • Suggested strategy: iOS may benefit from NSFetchedResultsController
  • Suggested strategy: Android might benefit from using the ListStore from FluxC.
• The fetching and updating of the data should be transparent to users. ie they shouldn't be waiting on the fetch or unnecessarily loosing "progress" by not having the same template selected.
• Future iteration consider pull to refresh.
• This should also handle the caching of Image data

Additional context

Blueprint Flow - iOS

Blueprint Flow - Android