+ This does not cover on-keydown handlers within elements.
A follow-up change will account for those.
+ Keyboard shortcuts are disabled within gr-overlay, input,
and textarea elements.
+ Added tests for new behavior (plus some missing ones covering
broken behavior).
+ Removed blur hacks used on elements to placate the kb
shortcuts due to restrictions that have been removed.
Bug: Issue 4198
Change-Id: Ide8009a3bfc340a35a8ec8b9189a85b49c8a95aa
4d22c7e835