logd: propagate ::log status

Add a return value for the ::log() methods, this allows
us to optimize the wakeup for the readers to only occur
when the log message is actually placed.

This is for a future where we may dedupe identical log
messages, filter out log messages, and certainly if we
filter the messages out with an internal logd check of
__android_log_is_loggable().

Change-Id: I763b2a7c29502ab7fa0a5d5022c7b60244fcfde4
5 files changed
tree: 7a01e5b3774cbf25f26423905dbce0b05fb71ed9
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/