Pass extension instance to JS hook views

Review Request #8594 — Created Jan. 5, 2017 and submitted — Latest diff uploaded

Information

Review Board
master
a2d7aae...

Reviewers

This makes it easy to pass e.g. extra model data from Python
JSExtension::get_model_data() to the view.

Verified that the extension instance is available in a ReviewDialogHookView.