Merge "Only cache mini bitmap wallpaper when there are widgets" into sc-v2-dev...

Merge "Only cache mini bitmap wallpaper when there are widgets" into sc-v2-dev am: 4743b44c am: 7f003540

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16066645

Change-Id: I35ea7221daf44a641d47ccfea2a17e4695b36e19