Right now we assume that every ContentHolder with a page bundle is Parsoid content, but there are some code paths (LanguageConverter fallback and ShadowPages) where this isn't the case.
ContentHolder::createFromParsoidPageBundle() should probably become ::createFromPageBundle() with isParsoidContent as a boolean argument, and then we should hoist that boolean into every place that uses that ContentHolder constructor.
Change #1307885 had a related patch set uploaded (by C. Scott Ananian; author: C. Scott Ananian):
[mediawiki/core@master] Inline LanguageVariantConverter::convertPageBundleVariant into ParsoidHandler
Change #1307886 had a related patch set uploaded (by C. Scott Ananian; author: C. Scott Ananian):
[mediawiki/core@master] Allow ContentHolder to hold PageBundles for non-Parsoid output
Change #1307889 had a related patch set uploaded (by C. Scott Ananian; author: C. Scott Ananian):
[mediawiki/core@master] PageBundleParserOutputConverter: Don't emit <base href> for non-Parsoid content
Change #1307889 merged by jenkins-bot:
[mediawiki/core@master] PageBundleParserOutputConverter: Don't emit <base href> for non-Parsoid content
Change #1307885 merged by jenkins-bot:
[mediawiki/core@master] Inline LanguageVariantConverter::convertPageBundleVariant into ParsoidHandler