Queue messages in LogReader::State

This gives us an interface to run the noncausal time offset filter.

Change-Id: I251714f3a6bcd78dd5cae8fd7089ca078e1663c4
diff --git a/aos/events/logging/logfile_utils.cc b/aos/events/logging/logfile_utils.cc
index 6dbc36f..ade82f9 100644
--- a/aos/events/logging/logfile_utils.cc
+++ b/aos/events/logging/logfile_utils.cc
@@ -1098,7 +1098,7 @@
   return true;
 }
 
-monotonic_clock::time_point ChannelMerger::OldestMessage() const {
+monotonic_clock::time_point ChannelMerger::OldestMessageTime() const {
   if (channel_heap_.empty()) {
     return monotonic_clock::max_time;
   }