Merge "Include <functional> for std::function and std::placeholders" into main am: e5896f0fea am: 073c14a320

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2674342

Change-Id: I6af09129d24876e8582ab2121512dd16b1ec3492
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>