Use toKeyboardEvent instead of static_cast<KeyboardEvent*>.

BUG=

Review URL: https://chromiumcodereview.appspot.com/17810002

git-svn-id: svn://svn.chromium.org/blink/trunk@153062 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Suppress reporting "!ie" hack, unicode-bidi:isolate and vendor-specific pseudoclasses

R=vsevik@chromium.org
BUG=254351

Review URL: https://codereview.chromium.org/17852002

git-svn-id: svn://svn.chromium.org/blink/trunk@153063 bbb929c8-8fbe-4397-9dbb-9b2b20218538