HTMLTreeBuilder shouldn't keep a Document pointer
https://bugs.webkit.org/show_bug.cgi?id=106268

Reviewed by Eric Seidel.

The tree builder shouldn't interact with the Document directly.
Instead, the tree builder should use the HTMLConstructionSite to
interact with the document.

Unfortunately, the HTMLTreeBuilder does need to read back one bit of
information (the quirks mode) from the Document. Currently the
HTMLConstructionSite reads the information directly from the Document.
If/when we move the parser onto its own thread, we'll need to keep
track of this bit on the parser thread. (We should be able to
encapsulate all that logic in the HTMLConstructionSite.)

* html/parser/HTMLConstructionSite.cpp:
(WebCore::HTMLConstructionSite::setDefaultCompatibilityMode):
(WebCore):
(WebCore::HTMLConstructionSite::finishedParsing):
(WebCore::HTMLConstructionSite::inQuirksMode):
* html/parser/HTMLConstructionSite.h:
(HTMLConstructionSite):
* html/parser/HTMLTreeBuilder.cpp:
(WebCore::HTMLTreeBuilder::HTMLTreeBuilder):
(WebCore::HTMLTreeBuilder::detach):
(WebCore::HTMLTreeBuilder::processStartTagForInBody):
(WebCore::HTMLTreeBuilder::defaultForInitial):
(WebCore::HTMLTreeBuilder::finished):
* html/parser/HTMLTreeBuilder.h:
(HTMLTreeBuilder):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@139042 268f45cc-cd09-0410-ab3c-d52691b4dbfc