[cleanup] Remove useless includes.

Manual cleanup guided by include-what-you-use diagnostic.

Bug: webrtc:8311
Change-Id: I00be03392cc7ee005101427ea7dc701621ccea68
Reviewed-on: https://webrtc-review.googlesource.com/c/103320
Commit-Queue: Yves Gerey <yvesg@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25013}
diff --git a/rtc_base/messagequeue.cc b/rtc_base/messagequeue.cc
index a561af4..84d3a96 100644
--- a/rtc_base/messagequeue.cc
+++ b/rtc_base/messagequeue.cc
@@ -8,13 +8,14 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <algorithm>
+#include <utility>  // for move
 
 #include "rtc_base/atomicops.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/messagequeue.h"
-#include "rtc_base/stringencode.h"
 #include "rtc_base/thread.h"
+#include "rtc_base/timeutils.h"  // for TimeMillis, TimeDiff, TimeUntil
 #include "rtc_base/trace_event.h"
 
 namespace rtc {