Refactoring: Removing unused variables and duplicate function call.

Removed few unused variables and got rid of duplicate
function call to 'Position::upstream'.

R=ojan, yosin

Review URL: https://codereview.chromium.org/25754003

git-svn-id: svn://svn.chromium.org/blink/trunk@158857 bbb929c8-8fbe-4397-9dbb-9b2b20218538