(4) Rename files to snake_case: update BUILD.gn, include paths, header guards, and DEPS entries

Mechanically generated by running this command:

tools_webrtc/do-renames.sh update all-renames.txt && git cl format

Then manually updating:

tools_webrtc/sanitizers/tsan_suppressions_webrtc.cc

Bug: webrtc:10159
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I54824cd91dada8fc3ee3d098f971bc319d477833
Reviewed-on: https://webrtc-review.googlesource.com/c/115653
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26226}
diff --git a/modules/video_coding/video_coding_impl.h b/modules/video_coding/video_coding_impl.h
index 08b0753..e6b1215 100644
--- a/modules/video_coding/video_coding_impl.h
+++ b/modules/video_coding/video_coding_impl.h
@@ -26,7 +26,7 @@
 #include "modules/video_coding/jitter_buffer.h"
 #include "modules/video_coding/receiver.h"
 #include "modules/video_coding/timing.h"
-#include "rtc_base/onetimeevent.h"
+#include "rtc_base/one_time_event.h"
 #include "rtc_base/sequenced_task_checker.h"
 #include "rtc_base/thread_annotations.h"
 #include "rtc_base/thread_checker.h"