logd: start cleaning up LogReaderThread

1) We can use real member functions with std::thread and
   std::function, so use those instead of the 'me' pointer.
2) Don't expose member variables directly.
3) Rename and document member variables, since all of their references
   are being touched anyway.

Test: logging unit tests
Change-Id: I9a357a3ea8691433d58687c95356b984b83e9c36
diff --git a/logd/LogReader.h b/logd/LogReader.h
index e50ca8e..f00cc21 100644
--- a/logd/LogReader.h
+++ b/logd/LogReader.h
@@ -29,7 +29,7 @@
 
    public:
     explicit LogReader(LogBuffer* logbuf);
-    void notifyNewLog(log_mask_t logMask);
+    void notifyNewLog(unsigned int logMask);
 
     LogBuffer& logbuf(void) const {
         return mLogbuf;