(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/media/base/rtp_data_engine.h b/media/base/rtp_data_engine.h
index 42e9190..f24b224 100644
--- a/media/base/rtp_data_engine.h
+++ b/media/base/rtp_data_engine.h
@@ -8,17 +8,17 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef MEDIA_BASE_RTPDATAENGINE_H_
-#define MEDIA_BASE_RTPDATAENGINE_H_
+#ifndef MEDIA_BASE_RTP_DATA_ENGINE_H_
+#define MEDIA_BASE_RTP_DATA_ENGINE_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
-#include "media/base/mediachannel.h"
-#include "media/base/mediaconstants.h"
-#include "media/base/mediaengine.h"
+#include "media/base/media_channel.h"
+#include "media/base/media_constants.h"
+#include "media/base/media_engine.h"
 
 namespace rtc {
 class DataRateLimiter;
@@ -109,4 +109,4 @@
 
 }  // namespace cricket
 
-#endif  // MEDIA_BASE_RTPDATAENGINE_H_
+#endif  // MEDIA_BASE_RTP_DATA_ENGINE_H_