Use the facility added in core change I055abdf4d to deduplicate the
embedded style rules.
Bug: T168333
Change-Id: I98c6d5ca4b474de8826b19355f15a5230aef5650
Depends-On: I055abdf4d73ec65771eaa4fe0999ec907c831568
* Fix test for TemplateStylesFontFaceAtRuleSanitizer so it's actually run
* Hack up a broken Sanitizer to test a code path in
TemplateStylesContent::sanitize() that handles such things.
* Ignore an InvalidArgumentException in TemplateStylesContent::processError()
that's not worth checking. User input can't hit that, only logic bugs.
* Ignore TemplateStylesHooks::getConfig(), it's tested but gets called
before PHPUnit starts counting.
* Test TemplateStylesHooksTest::onCodeEditorGetPageLanguage()
* Test $wgTemplateStylesDisable
* Test a back-compat code path in TemplateStylesHooks::handleTag().
Change-Id: I7078e5a353a624aa53fe72de7990b93a77b44cf6