logd: worst uid record watermark part four

With part deux we caused an apparent regression by not checking for
stale recorded iterators. This checking was on-purpose bypassesed
when leading prune entries were to be deleted without touching the
statistics engine due to an in-place merge.

Part deux had us leaving iterators we were not focussed on untouched
which in turn because they were left behind, had a much higher
likelihood of being deleted without touching the statistics engine.

Perform the check every delete.

Bug: 23789348
Change-Id: Idc6cc23d1f9e3b6cd9a083139a0de59479fbfe08
diff --git a/logd/LogBuffer.h b/logd/LogBuffer.h
index fcb05f5..de76693 100644
--- a/logd/LogBuffer.h
+++ b/logd/LogBuffer.h
@@ -87,7 +87,8 @@
 private:
     void maybePrune(log_id_t id);
     void prune(log_id_t id, unsigned long pruneRows, uid_t uid = AID_ROOT);
-    LogBufferElementCollection::iterator erase(LogBufferElementCollection::iterator it);
+    LogBufferElementCollection::iterator erase(
+        LogBufferElementCollection::iterator it, bool engageStats = true);
 };
 
 #endif // _LOGD_LOG_BUFFER_H__