Simplify some is-this-a-MathML-element? checks.
<https://webkit.org/b/124119>

As of r158198, the MathML-ness of an Element is determined by
a Node flag, so there's no need to cast to Element before checking
on this. Simplify accordingly.

Reviewed by Antti Koivisto.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159021 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Remove unused FragmentationDisabler class.
<https://webkit.org/b/124118>

This RAII object was added in r144744 to avoid a crash when using
MathML inside CSS regions. Its only user was removed in r157070.

Reviewed by Antti Koivisto.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159022 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Generate type casting helpers for Widget classes.
<https://webkit.org/b/124120>

Add a WIDGET_TYPE_CASTS macro and replace all the hand-written
toFoo() helpers we had for Widget subclasses. Fixed up a handful
of places that were still using static_cast.

Reviewed by Antti Koivisto.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159023 268f45cc-cd09-0410-ab3c-d52691b4dbfc