[Refactor] Consolidate the logic for whether a widget can be activated.

ash/sticky_keys/sticky_keys_overlay.cc

Index: ash/sticky_keys/sticky_keys_overlay.cc
diff --git a/ash/sticky_keys/sticky_keys_overlay.cc b/ash/sticky_keys/sticky_keys_overlay.cc
index 2613110879aebb8f5e3266a4362ae0acd36d2a1d..7720ad68f8e17080979f8a60beccbbda34d16114 100644
--- a/ash/sticky_keys/sticky_keys_overlay.cc
+++ b/ash/sticky_keys/sticky_keys_overlay.cc
@@ -227,7 +227,6 @@ StickyKeysOverlay::StickyKeysOverlay()
   params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
   params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   params.accept_events = false;
-  params.can_activate = false;
   params.keep_on_top = true;
   params.remove_standard_frame = true;
   params.delegate = overlay_view_;