(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/audio_processing/audio_processing_unittest.cc b/modules/audio_processing/audio_processing_unittest.cc
index 314d777..6ae6765 100644
--- a/modules/audio_processing/audio_processing_unittest.cc
+++ b/modules/audio_processing/audio_processing_unittest.cc
@@ -28,20 +28,20 @@
 #include "modules/audio_processing/test/test_utils.h"
 #include "rtc_base/arraysize.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/fakeclock.h"
+#include "rtc_base/fake_clock.h"
 #include "rtc_base/gtest_prod_util.h"
 #include "rtc_base/ignore_wundef.h"
 #include "rtc_base/numerics/safe_conversions.h"
 #include "rtc_base/numerics/safe_minmax.h"
 #include "rtc_base/protobuf_utils.h"
-#include "rtc_base/refcountedobject.h"
+#include "rtc_base/ref_counted_object.h"
 #include "rtc_base/strings/string_builder.h"
 #include "rtc_base/swap_queue.h"
 #include "rtc_base/system/arch.h"
 #include "rtc_base/task_queue.h"
 #include "rtc_base/thread.h"
 #include "test/gtest.h"
-#include "test/testsupport/fileutils.h"
+#include "test/testsupport/file_utils.h"
 
 RTC_PUSH_IGNORING_WUNDEF()
 #ifdef WEBRTC_ANDROID_PLATFORM_BUILD