Fix the handling of min/max sizes in DesktopWindowTreeHostMus

As I checked with DesktopWindowTreeHostX11, it computes the max
and min sizes on SizeConstraintsChanged(), BoundsChanged(), and
the initial Show().

With this CL, now OverlayWindowViews does not have to set those
properties. This will also fix some app window's resizing.

Bug: none
Test: manually
Change-Id: I41ff2baba7807b3311d098d6a1ff050f271903ec
Reviewed-on: https://chromium-review.googlesource.com/c/1447047
Commit-Queue: Jun Mukai <mukai@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628124}
4 files changed