Add quotes support to MediaQueryTokenizer

Enable the MediaQueryTokenizer, and the MediaQueryParser through it, to handle quotes properly (mainly their error handling).
The tokenizer now generates StringTokens, which the parser considers invalid.


BUG=358816

Review URL: https://codereview.chromium.org/221243005

git-svn-id: svn://svn.chromium.org/blink/trunk@170752 bbb929c8-8fbe-4397-9dbb-9b2b20218538