Revert "SF: use shared_ptr to track hwcLayer"

This reverts commit 5d89c1d6.

The original commit was part of a larger set that has been backed
out temporarily while some bugs are sorted out.   This change
should have been backed out as well as it depends on the others
in the larger change.

Test: run cts -m CtsViewTestCases
Bug: 79264214

Change-Id: Ifa9388d9f9573073832a40075317fdabf74b180c