Introduce a SVGUnknownElement class for unknown SVG elements

[Chris Dumez]

Introduce a SVGUnknownElement class and have it override rendererIsNeeded() to return false. We now use SVGUnknownElement type (instead of SVGElement) for unknown SVG elements:
- Unknown Elements in SVG namespace
- Registered custom tag elements in SVG namespace (http://www.w3.org/TR/2013/WD-custom-elements-20130514/#registering-custom-elements)

As a consequence, SVGElement::rendererIsNeeded() is not longer required to return false and it will be able to behave as SVGStyledElement::rendererIsNeeded() once we merge SVGStyledElement into SVGElement.

This is a pre-requirement to merging SVGStyledElement into SVGElement (Bug 107386).

Corresponding Blink revision:
https://src.chromium.org/viewvc/blink?revision=155426&view=revision

[Chris Dumez]

Created attachment 209347 [details]
Patch

[Andreas Kling]

Comment on attachment 209347 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=209347&action=review

r=me

> Source/WebCore/svg/SVGUnknownElement.h:41
> +class SVGUnknownElement : public SVGElement {

This class should be FINAL since it has no subclasses.

[Chris Dumez]

Created attachment 209349 [details]
Patch for landing

Made the class FINAL.

[WebKit Commit Bot]

Comment on attachment 209349 [details]
Patch for landing

Clearing flags on attachment: 209349

Committed r154443: <http://trac.webkit.org/changeset/154443>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.