Add a test for media control dropoff

Add a test for media control dropoff
https://bugs.webkit.org/show_bug.cgi?id=151287
<rdar://problem/23544666>

Reviewed by Antoine Quint.

Source/WebCore:

Test: media/controls/inline-elements-dropoff-order.html

* Modules/mediacontrols/mediaControlsApple.js: Expose more state to testing.
* testing/InternalSettings.cpp:
(WebCore::InternalSettings::setAllowsAirPlayForMediaPlayback): Renamed from setWirelessPlaybackDisabled.
(WebCore::InternalSettings::setWirelessPlaybackDisabled): Deleted.
* testing/InternalSettings.h:
* testing/InternalSettings.idl:

LayoutTests:

* media/controls/inline-elements-dropoff-order-expected.txt: Added.
* media/controls/inline-elements-dropoff-order.html: Added.
* platform/mac-yosemite/media/controls: Added.
* platform/mac-yosemite/media/controls/inline-elements-dropoff-order-expected.txt: Added.
* platform/mac-elcapitan/media/controls: Added.
* platform/mac-elcapitan/media/controls/inline-elements-dropoff-order-expected.txt: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@203057 268f45cc-cd09-0410-ab3c-d52691b4dbfc