ClusterFuzz  collects coverage information for fuzzers it runs. Right now we are using a standalone tool to generate individual coverage reports.

To improve usability (and visibility) of these reports we'd like to integrate the information into Chromium Code Search. A special "Libfuzzer Coverage" layer would be ideal.

The layer will provide following annotations:

- line coverage information for some lines (covered/not covered). Should be   displayed in the source.
- aggregate information per folder. (covered/uncovered blocks, covered/uncovered functions).
- function coverage information for outline view.

Coverage information ideally should also include a name of the fuzzer that generated the coverage (display it in the gutter?).