This breaks gr-diff-view into three components:
+ gr-diff-view: manages keyboard shortcuts and fetching
change information.
+ gr-diff: fetches diff, comment, and draft data. Normalizes
it for use in rendering via gr-diff-side.
+ gr-diff-side: renders the normalized model constructed in
gr-diff.
Comments are not implemented using the new model for the
sake of the reviewer's sanity.
Feature: Issue 3648
Feature: Issue 3663
Change-Id: I60b8a61ef4349d0b7e45b105bb704aa1c07cd358
1aa7b90258