Merge "Tweak RuntimeInit docs around MimeMap registration."

        RuntimeHooks.setTimeZoneIdSupplier(() -> SystemProperties.get("persist.sys.timezone"));

        /*

         * Set a default mapping between MIME types and file extensions.

         * Replace libcore's minimal default mapping between MIME types and file

         * extensions with a mapping that's suitable for Android. Android's mapping

         * contains many more entries that are derived from IANA registrations but

         * with several customizations (extensions, overrides).

         */

        MimeMap.setDefault(MimeMapImpl.createDefaultInstance());