Tracking bug to upstream unit tests for MR extension code that we've upstreamed.

We should look into enabling these tests on the waterfall as well.

A few notes:
- Our tests are written using Jasmine, so we will need to add in a copy of the Jasmine library to third_party. third_party also has Qunit (which is used by remoting tests). But it would be a huge pain to have to rewrite all of our tests, due to difference in syntax and style.
- We will need to write a thin wrapper to report results to the window.domAutomationController object injected by browser tests. The existing model for running JS tests is a bit heavyweight, but I haven't seen any alternatives thus far. 
- We may need to include a copy of the Closure library with the unit tests.

(Background: https://groups.google.com/a/chromium.org/forum/#!searchin/chromium-dev/jasmine/chromium-dev/yAOY7qGIYwg/ghZMycMcu6sJ)