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: I6e7a7827f85f5a7cb329b7cc62bba8803d0d2a7c