Add hack for the "DomWrapperWorld::existingWindowShellWorkaroundWorld"

This will need to be fixed in blink first

BUG=none
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/136583003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244497 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244497