Text decorations should be listed as non-inheritable

Both "text-decoration" specs (CSS 2.1, CSS 3) and "text-decoration-line
spec (CSS 3) states these properties are not inherited (w/ exceptions,
which are currently handled by -in-effect property), however those were
listed as inherited for no reason - thus preserving behavior as shown by
layout test results.

BUG=165462

Review URL: https://chromiumcodereview.appspot.com/20751008

git-svn-id: svn://svn.chromium.org/blink/trunk@155560 bbb929c8-8fbe-4397-9dbb-9b2b20218538