LibFuzzer-based fuzzing is extremely efficient, more reliable, and usually thousands of times faster than traditional out-of-process fuzzing. By in-process, we mean that we dont launch a new process for every test case, and that we use compile-time instrumentation of the source code. By fuzzing, we measure code coverage for every input, and accumulate test cases that increase overall coverage. We hope all Chromium developers and external security researchers will contribute to this effort.”]
Source: https://security.googleblog.com/2016/08/guided-in-process-fuzzing-of-chrome.html