There are more entry points into WebGL than the public API. For example, drawing a WebGL canvas into another canvas.
<rdar://problem/16176389>
Created attachment 225287 [details] Patch
Comment on attachment 225287 [details] Patch Provisional r=me!
Comment on attachment 225287 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=225287&action=review > Source/WebCore/html/canvas/WebGLRenderingContext.cpp:811 > + return 0; nullptr
Committed r164744: <http://trac.webkit.org/changeset/164744>