macviews: reset closure animation on ReallyAccept

Accept() can be called more than once on the same MenuController, via context
menus; in this situation, it's important to clear the animation so that input
events get handled after the animation completes.

Bug: 833048
Change-Id: Id3ac92ce91e78b57f2120d4527e35e597ea03067
Reviewed-on: https://chromium-review.googlesource.com/1012876
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551410}

ui/views/controls/menu/menu_controller.cc

@@ -1493,6 +1493,11 @@ void MenuController::Accept(MenuItemView* item, int event_flags) {
 void MenuController::ReallyAccept(MenuItemView* item, int event_flags) {
   DCHECK(IsBlockingRun());
   result_ = item;
+#if defined(OS_MACOSX)
+  // Reset the closure animation since it's now finished - this also unblocks
+  // input events for the menu.
+  menu_closure_animation_.reset();
+#endif
   if (item && !menu_stack_.empty() &&
       !item->GetDelegate()->ShouldCloseAllMenusOnExecute(item->GetCommand())) {
     SetExitType(EXIT_OUTERMOST);