Move RtcEventLog object from inside VoiceEngine to Call.

webrtc/call/rtc_event_log.cc

Index: webrtc/call/rtc_event_log.cc
diff --git a/webrtc/call/rtc_event_log.cc b/webrtc/call/rtc_event_log.cc
index 7ea1e167a1e0a15e905c1e47bb722de84b97018f..840b210d15378dbbdf1ee079886674fe6064d27b 100644
--- a/webrtc/call/rtc_event_log.cc
+++ b/webrtc/call/rtc_event_log.cc
@@ -38,9 +38,7 @@
 
 namespace webrtc {
 
-#ifndef ENABLE_RTC_EVENT_LOG
-
-// No-op implementation if flag is not set.
+// No-op implementation is used if flag is not set, or in tests.
 class RtcEventLogNullImpl final : public RtcEventLog {
  public:
   bool StartLogging(const std::string& file_name,
@@ -74,7 +72,7 @@ class RtcEventLogNullImpl final : public RtcEventLog {
                              int32_t total_packets) override {}
 };
 
-#else  // ENABLE_RTC_EVENT_LOG is defined
+#ifdef ENABLE_RTC_EVENT_LOG
 
 class RtcEventLogImpl final : public RtcEventLog {
  public:
@@ -465,4 +463,8 @@ std::unique_ptr<RtcEventLog> RtcEventLog::Create(const Clock* clock) {
 #endif  // ENABLE_RTC_EVENT_LOG
 }
 
+std::unique_ptr<RtcEventLog> RtcEventLog::CreateNull() {
+  return std::unique_ptr<RtcEventLog>(new RtcEventLogNullImpl());
+}
+
 }  // namespace webrtc