Force display:none for audio elements with no controls attribute

Force display:none for audio elements with no controls attribute

In label-contains-other-interactive-content.html there is an audio
element which is clicked twice, first without the controls attribute and
then again after adding it.

When there is no controls attribute the element doesn't have a layout
object, so that amounted to clicking at (0,0). Due to the bug addressed
here, adding the controls attribute also didn't cause the layout object
to be created when it should, so the second click was also at (0,0).

These two clicks add up to a double click, triggering a selection in the
page. This is the cause of the test failure in a seemingly unrelated
change: https://codereview.chromium.org/838003005/

Change label-contains-other-interactive-content.html to not (fail to)
click on the audio element with no controls attribute, as it's far from
obvious that clickElement(element) will click (0,0) instead.

BUG=497120
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196671

[philipj_slow, 2015-06-08 10:38:45]

The CQ bit was checked by philipj@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2015-06-08 10:39:02]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1166743004/1

[commit-bot: I haz the power, 2015-06-08 11:29:39]

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

[commit-bot: I haz the power, 2015-06-08 11:29:40]

Dry run: This issue passed the CQ dry run.

[philipj_slow, 2015-06-08 11:33:00]

philipj@opera.com changed reviewers:
+ rune@opera.com

[philipj_slow, 2015-06-08 11:33:00]

PTAL, instead of https://codereview.chromium.org/838003005/

[philipj_slow, 2015-06-08 11:33:17]

On 2015/06/08 11:33:00, philipj wrote:
> PTAL, instead of https://codereview.chromium.org/838003005/

Sorry, I meant https://codereview.chromium.org/1170583002/

[rune, 2015-06-08 12:32:34]

lgtm

[philipj_slow, 2015-06-08 12:40:08]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2015-06-08 12:40:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1166743004/1

[commit-bot: I haz the power, 2015-06-08 12:44:12]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196671