Summary:
Render coverage information in the right gutter, if available.
We could render some kind of summary report deal too but this seems like a good
start.
Test Plan:
- Looked at diffs with coverage.
- Looked at diffs without coverage.
- Used inline comments, diff-of-diff, "show more", "show entire file", "show
generated file", "undo". Nothing seemed disrupted by the addition of a 5th
column.
Reviewers: btrahan, tuomaspelkonen, jungejason
Reviewed By: btrahan
CC: zeeg, aran, epriestley
Maniphest Tasks: T140
Differential Revision: https://secure.phabricator.com/D1527
