DevTools: Forward [Hard] Reload shortcuts from the inspected page into the frontend

This will allow the Network and Timeline panels to
start recording events in a timely manner.

R=pfeldman,vsevik
NOTRY=true

Review URL: https://codereview.chromium.org/242113006

git-svn-id: svn://svn.chromium.org/blink/trunk@172031 bbb929c8-8fbe-4397-9dbb-9b2b20218538