Implement adding favorites.

This change deletes the AddFavoritesActivity in favor of the activity provided
to us by the Intent.ACTION_PICK intent.

Bug: 36841782
Test: SpeedDialUiItemLoaderTest
PiperOrigin-RevId: 193439522
Change-Id: Ie297abd2307c727d746f26ba99961de116636dc4
5 files changed