Fix nit which is unefficiant sequence to deleteMarkedNodes.

deleteMarkedNodes need to move postion to prevent unefficiant do while loop.

BUG=none

Review URL: https://codereview.chromium.org/246793004

git-svn-id: svn://svn.chromium.org/blink/trunk@172279 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed