Merge "Attempt to clear memory after keyguard PIN entry" into sc-dev am: f16b3f76 am: abd75290

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15502355

Change-Id: I21ca2d1e4c4a519808e4a4b4d2f56b60c446ded7