(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/pc/rtc_stats_collector.cc b/pc/rtc_stats_collector.cc
index d48ecc0..b1a44ee 100644
--- a/pc/rtc_stats_collector.cc
+++ b/pc/rtc_stats_collector.cc
@@ -8,7 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "pc/rtcstatscollector.h"
+#include "pc/rtc_stats_collector.h"
 
 #include <memory>
 #include <string>
@@ -17,16 +17,16 @@
 
 #include "absl/memory/memory.h"
 #include "api/candidate.h"
-#include "api/mediastreaminterface.h"
-#include "api/peerconnectioninterface.h"
-#include "media/base/mediachannel.h"
-#include "p2p/base/p2pconstants.h"
+#include "api/media_stream_interface.h"
+#include "api/peer_connection_interface.h"
+#include "media/base/media_channel.h"
+#include "p2p/base/p2p_constants.h"
 #include "p2p/base/port.h"
-#include "pc/peerconnection.h"
-#include "pc/rtcstatstraversal.h"
+#include "pc/peer_connection.h"
+#include "pc/rtc_stats_traversal.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/strings/string_builder.h"
-#include "rtc_base/timeutils.h"
+#include "rtc_base/time_utils.h"
 #include "rtc_base/trace_event.h"
 
 namespace webrtc {