Revert 157417 "Reorder the destruction sequence of Vector() to d..."

> Reorder the destruction sequence of Vector() to do less work.
> 
> This is a subset of previously reviewed CL,
> https://codereview.chromium.org/23531010/ that had to be reverted due to
> unknown reasons for a performance regression. Hence, relanding in pieces.
> 
> R=abarth@chromium.org, tsepez@chromium.org
> 
> Review URL: https://codereview.chromium.org/23451016

TBR=cevans@chromium.org

Review URL: https://codereview.chromium.org/23726029

git-svn-id: svn://svn.chromium.org/blink/trunk@157496 bbb929c8-8fbe-4397-9dbb-9b2b20218538