MenuControllerTest.EmulateItemSelectedEarly persists after reverting my patch

Oh ... that one isn't in unit_tests.

(yeah, ui_base_unittests is https://bugs.chromium.org/p/chromium/issues/detail?id=845687 if you happen to have any thoughts on that one :)

Okay, this is a test-only issue (but a real issue) wherein we cast a RWHV* to a RWHVMac*.

We can cast to a RWHVBase* safely.

I'm going to go with a patch instead of a revert, because this only affects test code.

This issue appears to be causing a significant number of failures on mac_chromium_rel_ng; if at all possible, please revert the CL. "Only affecting tests" still means it's liable to dramatically impact the CQ.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/95ff316f51b802ad2870ed8adb5b8dbb12a8dd99

commit 95ff316f51b802ad2870ed8adb5b8dbb12a8dd99
Author: Christopher Cameron <ccameron@chromium.org>
Date: Wed May 23 02:08:56 2018

MacViews: Fix ASAN errors in NativeViewHostMac

This was caused by a cast to RenderWidgetHostViewMac, which is
inappropriate in some tests. Cast only to RenderWidgetHostViewBase
instead.

TBR=sdy

Bug:  845688 
Change-Id: Id08887aeba5f18209a9b570d7a36548bdf59faa7
Reviewed-on: https://chromium-review.googlesource.com/1069750
Reviewed-by: ccameron <ccameron@chromium.org>
Reviewed-by: Sidney San Martín <sdy@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560892}
[modify] https://crrev.com/95ff316f51b802ad2870ed8adb5b8dbb12a8dd99/content/browser/renderer_host/render_widget_host_view_base.cc
[modify] https://crrev.com/95ff316f51b802ad2870ed8adb5b8dbb12a8dd99/content/browser/renderer_host/render_widget_host_view_base.h
[modify] https://crrev.com/95ff316f51b802ad2870ed8adb5b8dbb12a8dd99/content/browser/renderer_host/render_widget_host_view_mac.h
[modify] https://crrev.com/95ff316f51b802ad2870ed8adb5b8dbb12a8dd99/content/browser/web_contents/web_contents_view_mac.mm

unit_tests has cycled green

 Issue 845759  has been merged into this issue.

 Issue 845690  has been merged into this issue.

My analysis shows 845760, 845759, 845690 are (at least partially) related to
 bug 845687 , not this one. I made a revert of another change and am observing.

I'm pretty sure  issue 845760  (BrowserViewTest.BookmarkBarInvisibleOnShutdown),  issue 845759  (BrowserViewHostedAppTest.Layout),  issue 845690  (BrowserViewTest.AccessibleWindowTitle) are related to this bug. All 3 of those tests were failing in the ASAN builds.