* Execute content script in isolated world
* Inject script into newly created extension worlds
* Create new content_script_bundle for extension scripts
* Initialize chrome API in content script bundle
* Define Chrome extension isolated world ID range
1 << 20 was chosen as it provides a sufficiently large range of IDs for extensions, but also provides a large enough buffer for any user worlds in [1000, 1 << 20).
Ultimately this range can be changed if any user application raises it as an issue.
* Insert content script CSS into document
This now avoids a script wrapper to inject the style sheet. This closely matches the code used by chromium in `ScriptInjection::InjectCss`.
* Pass extension ID to isolated world via v8 private
