Add tests to avoid regeression on textarea.

LayoutTests/fast/forms/input-tab-shows-caret.html:
 Confirms tab fusing shows up caret. Needs rebaseline.

LayoutTests/fast/forms/textarea-select.html:
 textarea.select() selects right range of a value text.

BUG=399999, 400320, 400180

Review URL: https://codereview.chromium.org/444493003

git-svn-id: svn://svn.chromium.org/blink/trunk@179518 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Enable disabled animaition tests.

r176165 disabled three tests, but two are innocent.
overlay-background-color-transitions.html causes oom, and innocent two tests
were victim of oom. So enable them again.

BUG=384857

Review URL: https://codereview.chromium.org/432263003

git-svn-id: svn://svn.chromium.org/blink/trunk@179519 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Set fullscreenEnabled to false when fullscreen is not supported.

According to the latest version of the living standard,
fullscreenEnabled must be false if fullscreen is not supported:
http://fullscreen.spec.whatwg.org/

More details about the latest update to the standard:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=26479
https://github.com/whatwg/fullscreen/commit/d35a070d443632d0071b49318e40092667ac9801

Review URL: https://codereview.chromium.org/426593010

git-svn-id: svn://svn.chromium.org/blink/trunk@179520 bbb929c8-8fbe-4397-9dbb-9b2b20218538