Implement pipeline for a simple search based on query string matching on app names in WidgetsListBaseEntries.

This will be the default search for AOSP widget picker and a fallback search for Pixel widget picker.

Test: Tested prototype locally. Also added robolectric test.
Bug: b/157286785
Change-Id: Iad3bf2f46b2a89383a52c756fd1b9f65ecbeb40b
4 files changed