Merge "Add step down ramp to vibration waveforms" into sc-dev am: 50471a76...

Merge "Add step down ramp to vibration waveforms" into sc-dev am: 50471a76 am: beae8429 am: 7e981c93

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15143497

Change-Id: I033fa5f2b63c5119ed5aa8be48dcd4a63170eb8a