How best to architect the InstallTrigger code to support e10s

As part of the ongoing extension manager rewrite I'm changing a lot of 
the code that makes the InstallTrigger object available to content JS. 
As an overview the InstallTrigger object is what websites can use to 
test whether XPI installation is enabled and to start extension installs.

The question I have is how to best restructure the code such that when 
we move to e10s full on the transition is simple. My best guess would be 
something like this:

An object that implements InstallTrigger that would run in the content 
process and talks to an object in the chrome process (initially directly 
but presumably later through IPDL). From what I understand it is 
allowable for calls from the content process to the chrome process to be 
synchronous and block content, but not vice versa?

Is this along the right lines?

Dave