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

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

Change-Id: I2a1f29c5be71182a22e798e5c604753356f32c5a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>