Add an explicit full-screen button.

Add an explicit full-screen button.

We've recevied feedback that conflating maximized and full-screen is not what
users expect. This CL builds on https://codereview.chromium.org/498813003/ to
remove this functionality and instead add an explicit full-screen button to
the window frame.

Note that the icon is a placeholder until we can get UX resources to design a
better one.

BUG=404693
Committed: https://crrev.com/0bc497a8815f2142907a9609d261d30d7d13aefa
Cr-Commit-Position: refs/heads/master@{#291811}

[Jamie, 2014-08-25 18:18:01]

jamiewalch@chromium.org changed reviewers:
+ kelvinp@chromium.org

[Jamie, 2014-08-25 18:18:02]

ptal

[kelvinp, 2014-08-25 19:05:10]

lgtm

[Jamie, 2014-08-25 21:52:36]

The CQ bit was checked by jamiewalch@chromium.org

[commit-bot: I haz the power, 2014-08-25 21:53:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jamiewalch@chromium.org/491873004/20001

[commit-bot: I haz the power, 2014-08-26 00:34:02]

Committed patchset #2 (20001) as e1f924b936739b21e0ac9c53cff3ffc5cfe2c69b

[commit-bot: I haz the power, 2014-09-10 02:39:23]

Patchset 2 (id:??) landed as
https://crrev.com/0bc497a8815f2142907a9609d261d30d7d13aefa
Cr-Commit-Position: refs/heads/master@{#291811}