include what you use: errno.h and string.h in base/

Adding some missing errno.h includes for errno and
string.h for strerror in base/

Review URL: https://codereview.chromium.org/1434533004

Cr-Commit-Position: refs/heads/master@{#358477}


CrOS-Libchrome-Original-Commit: 522dfa59c94b0b49d0decee4af01f35730110bf1
4 files changed
tree: 24fbe7d8b9c4ac3b2d484cbe6d962cf78afd1557
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/