Pass the array buffer allocator to gin

BUG=none
R=dslomov@chromium.org,abarth@chromium.org

Review URL: https://codereview.chromium.org/172163002

git-svn-id: svn://svn.chromium.org/blink/trunk@167523 bbb929c8-8fbe-4397-9dbb-9b2b20218538