Add a UseCounter for the webkitallowfullscreen attribute

Add a UseCounter for the webkitallowfullscreen attribute

We support the unprefixed allowfullscreen attribute, so it would be nice
to also reflect it in HTMLIFrameElement.allowFullscreen. However, that's
tricky while there are two backing attributes, so first measure if the
prefixed attribute can be removed yet.

BUG=none

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170124

[philipj_slow, 2014-03-26 11:42:38]

falken, can you PTAL?
eseidel, can you be falken's rubberstamp?

[falken, 2014-03-26 13:59:31]

lgtm with a comment

https://codereview.chromium.org/212433004/diff/1/Source/core/dom/FullscreenEl...
File Source/core/dom/FullscreenElementStack.cpp (right):

https://codereview.chromium.org/212433004/diff/1/Source/core/dom/FullscreenEl...
Source/core/dom/FullscreenElementStack.cpp:49: static bool
allowFullscreenOnAllOwners(const Document& document)
nit: would isAllowFullscreenOnAllOwners or fullscreenIsAllowedOnAllOwners be
better? "allowFullscreen" looks like an action to me.

[philipj_slow, 2014-03-26 16:18:57]

https://codereview.chromium.org/212433004/diff/1/Source/core/dom/FullscreenEl...
File Source/core/dom/FullscreenElementStack.cpp (right):

https://codereview.chromium.org/212433004/diff/1/Source/core/dom/FullscreenEl...
Source/core/dom/FullscreenElementStack.cpp:49: static bool
allowFullscreenOnAllOwners(const Document& document)
On 2014/03/26 13:59:32, falken wrote:
> nit: would isAllowFullscreenOnAllOwners or fullscreenIsAllowedOnAllOwners be
> better? "allowFullscreen" looks like an action to me.

I wanted something with "allowfullscreen" in the name, but you're right. I'll go
with fullscreenIsAllowedForAllOwners to match fullScreenIsAllowedForElement.

[philipj_slow, 2014-03-27 01:34:44]

tkent, can you rubberstamp this?

[tkent, 2014-03-27 01:45:43]

lgtm

[philipj_slow, 2014-03-27 01:52:44]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2014-03-27 01:52:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/philipj@opera.com/212433004/80001

[commit-bot: I haz the power, 2014-03-27 01:56:08]

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

[commit-bot: I haz the power, 2014-03-27 01:56:09]

Try jobs failed on following builders:
  tryserver.blink on blink_presubmit

[tkent, 2014-03-27 02:00:29]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2014-03-27 02:00:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/philipj@opera.com/212433004/80001

[commit-bot: I haz the power, 2014-03-27 02:57:18]

Change committed as 170124