Remove calls to v8::Script::GetId, it's going to be removed.

R=haraken@chromium.org
BUG=

Review URL: https://codereview.chromium.org/292813005

git-svn-id: svn://svn.chromium.org/blink/trunk@174539 bbb929c8-8fbe-4397-9dbb-9b2b20218538