Revert "Update includes for webrtc/{base => rtc_base} rename (2/3)"

This reverts commit c3771cc4d37f5573fe53b7c7cff295a4f0f9560f.
(breaks downstream internal project)

BUG=webrtc:7634
NOTRY=True
NOPRESUBMIT=True

Review-Url: https://codereview.webrtc.org/2972463002 .
Cr-Commit-Position: refs/heads/master@{#18873}
diff --git a/webrtc/system_wrappers/source/trace_impl.cc b/webrtc/system_wrappers/source/trace_impl.cc
index 513327e..30a8816 100644
--- a/webrtc/system_wrappers/source/trace_impl.cc
+++ b/webrtc/system_wrappers/source/trace_impl.cc
@@ -15,8 +15,8 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "webrtc/rtc_base/atomicops.h"
-#include "webrtc/rtc_base/platform_thread.h"
+#include "webrtc/base/atomicops.h"
+#include "webrtc/base/platform_thread.h"
 #ifdef _WIN32
 #include "webrtc/system_wrappers/source/trace_win.h"
 #else