Limit number of active graphics contexts per web process

[Roger Fong]

We will limit number of active WebGL contexts per webprocess to 16.
This should essentially be thought of as your machine running out of resources after 16 contexts are active.

[Radar WebKit Bug Importer]

<rdar://problem/16888465>

[Roger Fong]

Actually this: <rdar://problem/16888459>

[Roger Fong]

Created attachment 231330 [details]
patch

[Roger Fong]

Created attachment 231349 [details]
better patch

[Dean Jackson]

Comment on attachment 231349 [details]
better patch

View in context: https://bugs.webkit.org/attachment.cgi?id=231349&action=review

> Source/WebCore/platform/graphics/mac/GraphicsContext3DMac.mm:118
> +        return 0;

return nullptr;

> Source/WebCore/platform/graphics/mac/GraphicsContext3DMac.mm:123
> +        return 0;

return nullptr;

> LayoutTests/webgl/many-contexts.html:13
> +	for (var i = 0; i < size; i++) {
> +		canvii[i] = document.createElement("canvas");
> +		canvii[i].width = 1;
> +		canvii[i].height = 1;
> +		var context = canvii[i].getContext("webgl", null);
> +	}

Weird indentation.

Also, I wonder if we should check that context == null at 1000 (assuming that we might raise the number above 16, but never to 1000).

[Roger Fong]

Committed http://trac.webkit.org/changeset/168666 with fixes.