Enabled canvas.getContext("webgl") on Desktop Chrome
https://bugs.webkit.org/show_bug.cgi?id=113079

Patch by Brandon Jones <bajones@chromium.org> on 2013-03-25
Reviewed by Dean Jackson.

Test: fast/canvas/webgl/webgl-unprefixed-context-id.html

* bindings/v8/custom/V8HTMLCanvasElementCustom.cpp:
(WebCore::V8HTMLCanvasElement::getContextMethodCustom):
* html/HTMLCanvasElement.cpp:
(WebCore::HTMLCanvasElement::getContext):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146795 268f45cc-cd09-0410-ab3c-d52691b4dbfc