Use exitFullscreen(), not fullyExitFullscreen(), in HTMLMediaElement

Use exitFullscreen(), not fullyExitFullscreen(), in HTMLMediaElement

For both <video controls> and HTMLVideoElement.webkitExitFullscreen()
it makes more sense to only exit one level of fullscreen.

There was no test coverage for the distinction, and it's very unlikely
that Web content could meaningfully depend on this.

BUG=399556
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179440

[philipj_slow, 2014-08-01 15:45:21]

PTAL

[acolwell GONE FROM CHROMIUM, 2014-08-01 15:49:40]

lgtm

[philipj_slow, 2014-08-01 16:39:30]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2014-08-01 16:40:45]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/philipj@opera.com/422023007/1

[commit-bot: I haz the power, 2014-08-01 17:57:10]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/20177)

[commit-bot: I haz the power, 2014-08-01 19:04:55]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-08-01 19:04:56]

Try jobs failed on following builders:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)

[philipj_slow, 2014-08-02 04:32:11]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2014-08-02 04:32:40]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/philipj@opera.com/422023007/1

[commit-bot: I haz the power, 2014-08-02 05:39:34]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)

[commit-bot: I haz the power, 2014-08-02 06:45:10]

Change committed as 179440