logd: Allow (some) headers to be individually importable

LogReader.h needs to be individually importable.

Fix a few others, drop includes of local includes, let them be
included in source instead and allow headers to be included
alphabetically. Was not a complete audit since goal was to
separate LogReader.h out from the pack.

Bug: 27242723
Change-Id: Ic7759ef90995e5bd285810706af33550c73cf5b5
diff --git a/logd/LogTimes.h b/logd/LogTimes.h
index 1117088..f5969df 100644
--- a/logd/LogTimes.h
+++ b/logd/LogTimes.h
@@ -27,6 +27,7 @@
 #include <log/log.h>
 
 class LogReader;
+class LogBufferElement;
 
 class LogTimeEntry {
     static pthread_mutex_t timesLock;