Revert of Remove WebSettings::setDisallowFullscreenForNonMediaElements(bool)

Revert of Remove WebSettings::setDisallowFullscreenForNonMediaElements(bool) (https://codereview.chromium.org/416013002/)

Reason for revert:
We need this for the Android WebView

Original issue's description:
> Remove WebSettings::setDisallowFullscreenForNonMediaElements(bool)
> 
> It is never called from Chromium.
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178831

TBR=jochen@chromium.org,qinmin@chromium.org,philipj@opera.com
NOTREECHECKS=true
NOTRY=true

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179048

[Ignacio Solla, 2014-07-28 16:43:55]

Created Revert of Remove
WebSettings::setDisallowFullscreenForNonMediaElements(bool)

[commit-bot: I haz the power, 2014-07-28 16:44:30]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/igsolla@chromium.org/422923002/1

[commit-bot: I haz the power, 2014-07-28 16:44:31]

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

[commit-bot: I haz the power, 2014-07-28 16:44:31]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[qinmin, 2014-07-28 17:39:37]

lgtm

[qinmin, 2014-07-28 17:39:42]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2014-07-28 17:39:53]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/igsolla@chromium.org/422923002/1

[commit-bot: I haz the power, 2014-07-28 17:40:20]

Change committed as 179048

[philipj_slow, 2014-07-28 20:09:00]

Why is this needed for Android WebView? It seems like a completely random kind
of setting to have...

[philipj_slow, 2014-07-29 07:45:24]

This should have a test, otherwise it will invariably break with refactoring.

It looks to me like this won't actually work correctly. The call to
enterFullScreenForElement in FullscreenElementStack::requestFullScreenForElement
will now silently fail, and it will be perpetually waiting for the
FullscreenElementStack::didEnterFullScreenForElement callback.

A better place for this would be together with the other "If any of the
following conditions are true, terminate these steps" in
FullscreenElementStack::requestFullScreenForElement.

[Ignacio Solla, 2014-07-29 09:53:21]

On 2014/07/28 20:09:00, philipj wrote:
> Why is this needed for Android WebView? It seems like a completely random kind
> of setting to have...

Because Android WebView does only currently support fullscreen for video. I'll
add support for non-video elements soon.

[Ignacio Solla, 2014-07-29 09:56:26]

On 2014/07/29 07:45:24, philipj wrote:
> This should have a test, otherwise it will invariably break with refactoring.

I will add the test in a subsequent patch:
https://codereview.chromium.org/428633004/

> 
> It looks to me like this won't actually work correctly. The call to
> enterFullScreenForElement in
FullscreenElementStack::requestFullScreenForElement
> will now silently fail, and it will be perpetually waiting for the
> FullscreenElementStack::didEnterFullScreenForElement callback.
> 
> A better place for this would be together with the other "If any of the
> following conditions are true, terminate these steps" in
> FullscreenElementStack::requestFullScreenForElement.

I agree, and I'm moving this into
FullscreenElementStack::requestFullScreenForElement
in the subsequent patch.