TokenPreloadScanner should be (mostly!) thread-safe
https://bugs.webkit.org/show_bug.cgi?id=109760

Reviewed by Eric Seidel.

This patch makes the bulk of TokenPreloadScanner thread-safe.  The one
remaining wart is processPossibleBaseTag because it wants to grub
around in the base tag's attributes. I have a plan for that, but it's
going to need to wait for the next patch.

* html/parser/HTMLPreloadScanner.cpp:
(WebCore::isStartTag):
(WebCore::isStartOrEndTag):
(WebCore::TokenPreloadScanner::identifierFor):
(WebCore::TokenPreloadScanner::inititatorFor):
(WebCore::TokenPreloadScanner::StartTagScanner::StartTagScanner):
(WebCore::TokenPreloadScanner::StartTagScanner::processAttributes):
(TokenPreloadScanner::StartTagScanner):
(WebCore::TokenPreloadScanner::processPossibleTemplateTag):
(WebCore::TokenPreloadScanner::processPossibleStyleTag):
(WebCore::TokenPreloadScanner::processPossibleBaseTag):
(WebCore::TokenPreloadScanner::scan):
(WebCore::HTMLPreloadScanner::scan):
* html/parser/HTMLPreloadScanner.h:
(WebCore):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142843 268f45cc-cd09-0410-ab3c-d52691b4dbfc