logd: create SimpleLogBuffer and implement ChattyLogBuffer in terms of it

Test: unit tests with SimpleLogBuffer
Change-Id: If6e29418645b5491df9b8aeef8f95bb786aeba93
9 files changed
tree: 65871c2bf0a1d3d71656354ebbbdc15e226d3f05
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/