XSSAuditor performance regression in M26

The refactoring we did for the threaded parser introduced a performance
regression in innerHTML because we'd boot up the XSSAuditor for fragment
parsing. This CL returns to our earlier behavior of not booting up the
XSSAuditor when parsing fragments.

BUG=230504
TBR=eseidel

Review URL: https://codereview.chromium.org/14327009

git-svn-id: svn://svn.chromium.org/blink/trunk@148792 bbb929c8-8fbe-4397-9dbb-9b2b20218538
3 files changed