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

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

Change-Id: Ia3f0e5cf2f9d3a7231ca5a3e9a5021f82710812f