Add fuzzer for base64 encoding / decoding

This CL adds two new fuzzers.
1. The encoding fuzzer base64 encodes the input, then decodes it back,
   expecting to get a string equal to the input.

2. The decoding fuzzer just attempts to decode the random bytes.

Bug: None
Change-Id: I7ef233c92354527ad62485df19f8c14fae324e50
Reviewed-on: https://chromium-review.googlesource.com/728387
Commit-Queue: Charlie Harrison <csharrison@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Ryan Sleevi <rsleevi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510321}

CrOS-Libchrome-Original-Commit: 45a9833453ae06f05e0261269be5f90155eeceb4
2 files changed
tree: d34255fe4cb4e557e79d497970e3746f014728be
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/