(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/api/media_transport_interface.h b/api/media_transport_interface.h
index 4531fe4..ee1b8e3 100644
--- a/api/media_transport_interface.h
+++ b/api/media_transport_interface.h
@@ -25,11 +25,11 @@
 
 #include "absl/types/optional.h"
 #include "api/array_view.h"
-#include "api/rtcerror.h"
+#include "api/rtc_error.h"
 #include "api/video/encoded_image.h"
-#include "rtc_base/copyonwritebuffer.h"
+#include "rtc_base/copy_on_write_buffer.h"
 #include "rtc_base/deprecation.h"
-#include "rtc_base/networkroute.h"
+#include "rtc_base/network_route.h"
 
 namespace rtc {
 class PacketTransportInternal;