Merge "Add explicit <mutex> include" into main am: 716c482c88

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/3459703

Change-Id: I47e942df0d3fa1eec02f73d78ca8f81750d259af
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>