(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/stats_collector_unittest.cc b/pc/stats_collector_unittest.cc
index 582b60d..4fdb8cd2 100644
--- a/pc/stats_collector_unittest.cc
+++ b/pc/stats_collector_unittest.cc
@@ -16,28 +16,28 @@
 #include "absl/types/optional.h"
 #include "api/audio_codecs/audio_encoder.h"
 #include "api/candidate.h"
-#include "api/datachannelinterface.h"
+#include "api/data_channel_interface.h"
 #include "call/call.h"
-#include "media/base/mediachannel.h"
+#include "media/base/media_channel.h"
 #include "modules/audio_processing/include/audio_processing_statistics.h"
-#include "pc/datachannel.h"
-#include "pc/mediastream.h"
-#include "pc/mediastreamtrack.h"
-#include "pc/statscollector.h"
-#include "pc/test/fakepeerconnectionforstats.h"
-#include "pc/test/fakevideotracksource.h"
-#include "pc/transportstats.h"
-#include "pc/videotrack.h"
-#include "rtc_base/fakesslidentity.h"
-#include "rtc_base/messagedigest.h"
-#include "rtc_base/nethelper.h"
-#include "rtc_base/refcountedobject.h"
-#include "rtc_base/rtccertificate.h"
+#include "pc/data_channel.h"
+#include "pc/media_stream.h"
+#include "pc/media_stream_track.h"
+#include "pc/stats_collector.h"
+#include "pc/test/fake_peer_connection_for_stats.h"
+#include "pc/test/fake_video_track_source.h"
+#include "pc/transport_stats.h"
+#include "pc/video_track.h"
+#include "rtc_base/fake_ssl_identity.h"
+#include "rtc_base/message_digest.h"
+#include "rtc_base/net_helper.h"
+#include "rtc_base/ref_counted_object.h"
+#include "rtc_base/rtc_certificate.h"
 #include "rtc_base/scoped_ref_ptr.h"
-#include "rtc_base/socketaddress.h"
-#include "rtc_base/sslidentity.h"
-#include "rtc_base/sslstreamadapter.h"
-#include "rtc_base/stringencode.h"
+#include "rtc_base/socket_address.h"
+#include "rtc_base/ssl_identity.h"
+#include "rtc_base/ssl_stream_adapter.h"
+#include "rtc_base/string_encode.h"
 #include "rtc_base/third_party/base64/base64.h"
 #include "rtc_base/thread.h"
 #include "test/gtest.h"