Merge "Move contents of FeatureFlags into FeatureFlagManager." into sc-v2-dev am: 8d08226fe6 am: 3a489f7c9c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16214995

Change-Id: I0fc27789aff39ba0991b4d8e7b377d674ccbaa1d