SF: Add a flag to guard the video detection feature

Video feature is still under development, so we should not be populating
layer history in scheduler if the feature is not turned on.

See go/surface-flinger-scheduler for more info

Test: manual
Bug: 123956502
Change-Id: I83eae3b5203a4e6b8976f9b7400711963eacbb34
3 files changed