views: don't open context menus for VKEY_APPS on Mac

On Mac, VKEY_APPS is actually the right command key, which is not supposed to
behave this way in menus.

Bug: 875559
Change-Id: I78329273f4ddd5c5cd9aed89669d46f722de118b
Reviewed-on: https://chromium-review.googlesource.com/1186705Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585522}

ui/views/controls/menu/menu_controller.cc

@@ -1413,6 +1413,7 @@ void MenuController::OnKeyDown(ui::KeyboardCode key_code) {
       CloseSubmenu();
       break;
 
+#if !defined(OS_MACOSX)
     case ui::VKEY_APPS: {
       Button* hot_view = GetFirstHotTrackedView(pending_state_.item);
       if (hot_view) {
@@ -1432,6 +1433,7 @@ void MenuController::OnKeyDown(ui::KeyboardCode key_code) {
       }
       break;
     }
+#endif
 
 #if defined(OS_WIN)
     // On Windows, pressing Alt and F10 keys should hide the menu to match the