Remove menu_marker from MenuButton.

This is always false except for in tests and menu_example.cc which is
not used. This helps simplify MenuButton for the Button cleanup task.

Bug: 901183
Change-Id: If5a3cf7b6ba1ce5618548d112df1c4404b2ae181
Reviewed-on: https://chromium-review.googlesource.com/c/1324375
Reviewed-by: Mitsuru Oshima <[email protected]>
Reviewed-by: Robert Flack <[email protected]>
Reviewed-by: Trent Apted <[email protected]>
Reviewed-by: Michael Wasserman <[email protected]>
Commit-Queue: Charlene Yan <[email protected]>
Cr-Commit-Position: refs/heads/master@{#607061}
19 files changed