WebGL shouldn't allocate a "length" Identifier just to move some numbers around
https://bugs.webkit.org/show_bug.cgi?id=115317

Reviewed by Dean Jackson.

Saw this while debugging an ammo.js bug.

* bindings/js/JSArrayBufferViewHelper.h:
(WebCore::setWebGLArrayWithTypedArrayArgument):
(WebCore::setWebGLArrayHelper):
(WebCore::constructArrayBufferViewWithTypedArrayArgument):
(WebCore::constructArrayBufferView):
* bindings/js/JSWebGLRenderingContextCustom.cpp:
(WebCore::toVector): Use the pre-computed "length" identifier instead of
allocating a new one for each vector operation. There are lots more
optimizations we could do here. This is a start.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149249 268f45cc-cd09-0410-ab3c-d52691b4dbfc