Replace static_casts with existing casting helper functions.

BUG=309516

Review URL: https://codereview.chromium.org/112393003

git-svn-id: svn://svn.chromium.org/blink/trunk@163681 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove keyboard input timeout for date, datetime-local, month, time, and week input types on non-Android.

We had a feature that a numeric field in a date/time input field reset keyboard
input state if a user typed nothing for one second. This behavior was annoying
for slow-typing users. We just remove it.

BUG=232296

Review URL: https://codereview.chromium.org/112513002

git-svn-id: svn://svn.chromium.org/blink/trunk@163682 bbb929c8-8fbe-4397-9dbb-9b2b20218538