Web Inspector: HTML Formatter - XML mode

Web Inspector: HTML Formatter - XML mode
https://bugs.webkit.org/show_bug.cgi?id=201758

Reviewed by Devin Rousso.

Source/WebInspectorUI:

* Tools/HTMLFormatter/index.html:
* Tools/SourceMaps/index.html:
Update Tools to more easily test XML.

* UserInterface/Proxies/FormatterWorkerProxy.js:
(WI.FormatterWorkerProxy.prototype.formatXML):
* UserInterface/Views/TextEditor.js:
(WI.TextEditor.prototype.hasFormatter):
(WI.TextEditor.prototype._startWorkerPrettyPrint):
Allow formatting XML content.

* UserInterface/Workers/Formatter/FormatterWorker.js:
(FormatterWorker.prototype.formatHTML):
(FormatterWorker.prototype.formatXML):
Expose "formatXML".

* UserInterface/Workers/Formatter/HTMLFormatter.js:
(HTMLFormatter.let.dom):
(HTMLFormatter):
(HTMLFormatter.prototype._shouldHaveNoChildren):
(HTMLFormatter.prototype._before):
(HTMLFormatter.prototype._after):
* UserInterface/Workers/Formatter/HTMLParser.js:
(HTMLParser.prototype.parseDocument):
* UserInterface/Workers/Formatter/HTMLTreeBuilderFormatter.js:
(HTMLTreeBuilderFormatter.prototype._isEmptyNode):
Give the HTMLFormatter and related classes an XML mode that
has less of the smarts of XML.

LayoutTests:

* inspector/formatting/formatting-xml-expected.txt: Added.
* inspector/formatting/formatting-xml.html: Added.
* inspector/formatting/resources/formatting-utilities.js:
(TestPage.registerInitializer.async.runFormattingTest):
* inspector/formatting/resources/xml-tests/atom-expected.xml: Added.
* inspector/formatting/resources/xml-tests/atom.xml: Added.
* inspector/formatting/resources/xml-tests/basic-expected.xml: Added.
* inspector/formatting/resources/xml-tests/basic.xml: Added.
* inspector/formatting/resources/xml-tests/rss-expected.xml: Added.
* inspector/formatting/resources/xml-tests/rss.xml: Added.
* inspector/formatting/resources/xml-tests/valid-html-invalid-xml-expected.xml: Added.
* inspector/formatting/resources/xml-tests/valid-html-invalid-xml.xml: Added.
* inspector/formatting/resources/xml-tests/xslt-expected.xml: Added.
* inspector/formatting/resources/xml-tests/xslt.xml: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@249867 268f45cc-cd09-0410-ab3c-d52691b4dbfc