[Mac] Disable QTKit by default on future OS X.

[Mac] Disable QTKit by default on future OS X.
https://bugs.webkit.org/show_bug.cgi?id=144082

Reviewed by Darin Adler.

Source/WebCore:

Settings::gQTKitEnabled defaults to false.

* page/Settings.cpp:

Source/WebKit/mac:

Default WebKitQTKitEnabledPreferenceKey to NO.

* WebView/WebPreferences.mm:
(+[WebPreferences initialize]):

Source/WebKit2:

QTKitEnabled defaults to false.

* Shared/WebPreferencesDefinitions.h:

LayoutTests:

Add a required BANDWIDTH field to the alternate playlist.

* http/tests/media/resources/hls/playlist-with-cookie.m3u8:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@183221 268f45cc-cd09-0410-ab3c-d52691b4dbfc