Merge "Include <functional> for std::function and std::placeholders" into main am: e5896f0fea am: 073c14a320 am: ce87f3a63d am: bc5e1931d8

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

Change-Id: Iba5281859ab87c6eda5b2d62eb3893a160eedaf6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>