Multithreaded WebGL is a bad idea - remove it
https://bugs.webkit.org/show_bug.cgi?id=136964
<rdar://problem/18399858>

Reviewed by Brent Fulgham.

Source/WebCore:

We should not allow multithreaded GL access. Remove the
feature.

* html/canvas/WebGLRenderingContext.cpp:
(WebCore::WebGLRenderingContext::create):
* page/Settings.in:
* platform/graphics/GraphicsContext3D.h:
(WebCore::GraphicsContext3D::Attributes::Attributes):
* platform/graphics/mac/GraphicsContext3DMac.mm:
(WebCore::GraphicsContext3D::GraphicsContext3D):

Source/WebKit/mac:

Remove the setting to allow multithreaded WebGL.

* WebView/WebPreferenceKeysPrivate.h:
* WebView/WebPreferences.mm:
(+[WebPreferences initialize]):
(-[WebPreferences multithreadedWebGLEnabled]): Deleted.
(-[WebPreferences setMultithreadedWebGLEnabled:]): Deleted.
* WebView/WebPreferencesPrivate.h:
* WebView/WebView.mm:
(-[WebView _preferencesChanged:]):

Source/WebKit2:

Remove the setting to allow multithreaded WebGL.

* Shared/WebPreferencesDefinitions.h:
* UIProcess/API/C/WKPreferences.cpp:
(WKPreferencesSetMultithreadedWebGLEnabled): Deleted.
(WKPreferencesGetMultithreadedWebGLEnabled): Deleted.
* UIProcess/API/C/WKPreferencesRefPrivate.h:
* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::updatePreferences):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@173776 268f45cc-cd09-0410-ab3c-d52691b4dbfc