Update MainMenu.xib to use Xcode 8.3.2, macOS 10.13.3.

This CL is not intended to have any behavior change.

We need to update some keyEquivalents in MainMenu.xib, and it is much easier to
update the whole file to use Xcode 8.3.2 than to try to get an instance of Xcode
5.1.1 running on a macOS 10.9.5 device.

We refrain from updating all xibs since most of them are going away with the
migration to Views, and historically, updating xibs has had subtle behavior
changes.

Bug: 851714
Change-Id: Ibae17d5d645a373f29549d08b9d3c1bf95c0b08a
Reviewed-on: https://chromium-review.googlesource.com/1106897
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568621}
2 files changed