binding: Simplifies ScriptController::updateSecurityOrigin().

There is unnecessary complexity in updateSecurityOrigin().  This CL
simplifies it and removes unused code.

BUG=

Review-Url: https://codereview.chromium.org/2553103002
Cr-Commit-Position: refs/heads/master@{#436858}
4 files changed