The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5017a33b6604deeb741251f845955c097b07baf3

commit 5017a33b6604deeb741251f845955c097b07baf3
Author: jaydasika <jaydasika@chromium.org>
Date: Thu Mar 31 01:06:22 2016

cc : Remove parent for mask and replica layers in LayerImpl

This CL also deletes some dead code.

BUG= 599170 
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1850493002

Cr-Commit-Position: refs/heads/master@{#384172}

[modify] https://crrev.com/5017a33b6604deeb741251f845955c097b07baf3/cc/layers/layer.h
[modify] https://crrev.com/5017a33b6604deeb741251f845955c097b07baf3/cc/layers/layer_impl.cc
[modify] https://crrev.com/5017a33b6604deeb741251f845955c097b07baf3/cc/layers/layer_impl.h
[modify] https://crrev.com/5017a33b6604deeb741251f845955c097b07baf3/cc/trees/damage_tracker_unittest.cc
[modify] https://crrev.com/5017a33b6604deeb741251f845955c097b07baf3/cc/trees/layer_tree_host_common_unittest.cc
[modify] https://crrev.com/5017a33b6604deeb741251f845955c097b07baf3/cc/trees/occlusion_tracker_unittest.cc