Stop using LOG macros in favor of RTC_ prefixed macros.

This CL has been generated with the following script:

for m in PLOG \
  LOG_TAG \
  LOG_GLEM \
  LOG_GLE_EX \
  LOG_GLE \
  LAST_SYSTEM_ERROR \
  LOG_ERRNO_EX \
  LOG_ERRNO \
  LOG_ERR_EX \
  LOG_ERR \
  LOG_V \
  LOG_F \
  LOG_T_F \
  LOG_E \
  LOG_T \
  LOG_CHECK_LEVEL_V \
  LOG_CHECK_LEVEL \
  LOG
do
  git grep -l $m | xargs sed -i "s,\b$m\b,RTC_$m,g"
done
git checkout rtc_base/logging.h
git cl format

Bug: webrtc:8452
Change-Id: I1a53ef3e0a5ef6e244e62b2e012b864914784600
Reviewed-on: https://webrtc-review.googlesource.com/21325
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20617}
diff --git a/sdk/objc/Framework/Classes/Common/RTCFileLogger.mm b/sdk/objc/Framework/Classes/Common/RTCFileLogger.mm
index afe61a8..15461f4 100644
--- a/sdk/objc/Framework/Classes/Common/RTCFileLogger.mm
+++ b/sdk/objc/Framework/Classes/Common/RTCFileLogger.mm
@@ -101,8 +101,7 @@
       break;
   }
   if (!_logSink->Init()) {
-    LOG(LS_ERROR) << "Failed to open log files at path: "
-                  << _dirPath.UTF8String;
+    RTC_LOG(LS_ERROR) << "Failed to open log files at path: " << _dirPath.UTF8String;
     _logSink.reset();
     return;
   }