libchrome: add base/functional/* headers am: 57f727b567 am: 316c1ca053 Original change: https://android-review.googlesource.com/c/platform/external/libchrome/+/2399915 Change-Id: If465796c2e93e6da661e773151492eba998a2007 Signed-off-by: Automerger Merge Worker <[email protected]>