I think you can just remove [1] and [2]

[1] https://cs.chromium.org/chromium/src/ash/shelf/shelf_controller.cc?rcl=e8f5e85dbe3382c038745fe94f23a924bf7cc17d&l=350
[2] https://cs.chromium.org/chromium/src/ash/shelf/shelf_context_menu_model.cc?rcl=e8f5e85dbe3382c038745fe94f23a924bf7cc17d&l=96

And modify [1]

[1] https://cs.chromium.org/chromium/src/ash/shelf/shelf_controller.cc?rcl=bd98c9e073fe87155f291420f54ad7c0260bceca&l=96

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0632cd6ccf8fd833f373263d2fc26bca19262159

commit 0632cd6ccf8fd833f373263d2fc26bca19262159
Author: Vladislav Kaznacheev <kaznacheev@google.com>
Date: Thu Aug 30 21:37:15 2018

Re-enable shelf auto-hide in tablet mode

- show auto-hide related menu option in tablet mode
- respect auto-hide bit in tablet mode if it is set in clamshell mode
- update test accordingly

  ash_unittests --gtest_filter=Shelf*

Bug:  878039 
Test: manual, ash_unittests --gtest_filter=TabletModeWindowManagerTest*,
Change-Id: I8a8688e794e243e4b2da026803dff9e136f3c1f1
Reviewed-on: https://chromium-review.googlesource.com/1196142
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587783}
[modify] https://crrev.com/0632cd6ccf8fd833f373263d2fc26bca19262159/ash/shelf/shelf_context_menu_model.cc
[modify] https://crrev.com/0632cd6ccf8fd833f373263d2fc26bca19262159/ash/shelf/shelf_context_menu_model_unittest.cc
[modify] https://crrev.com/0632cd6ccf8fd833f373263d2fc26bca19262159/ash/shelf/shelf_controller.cc
[modify] https://crrev.com/0632cd6ccf8fd833f373263d2fc26bca19262159/ash/shelf/shelf_controller_unittest.cc
[modify] https://crrev.com/0632cd6ccf8fd833f373263d2fc26bca19262159/ash/wm/tablet_mode/tablet_mode_window_manager_unittest.cc

 Issue 878041  has been merged into this issue.