Revert "Remove menu_marker from MenuButton."

This reverts commit 3275875871d7e5dd239acbe5ac6545d51a25cb3d.

Reason for revert: causes compile failures on windows similar to the ones that appeared in the CQ runs, e.g. https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win%20x64%20Builder/58688

Original change's description:
> 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 <oshima@chromium.org>
> Reviewed-by: Robert Flack <flackr@chromium.org>
> Reviewed-by: Trent Apted <tapted@chromium.org>
> Reviewed-by: Michael Wasserman <msw@chromium.org>
> Commit-Queue: Charlene Yan <cyan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#607061}

TBR=msw@chromium.org,flackr@chromium.org,oshima@chromium.org,tapted@chromium.org,cyan@chromium.org

Change-Id: I9c311a3c8cea56c7670b2dace3e0410618151034
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 901183
Reviewed-on: https://chromium-review.googlesource.com/c/1330841
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607072}
19 files changed