Hooked up RtcEventLog. It lives in Voice Engine and pointers are propagated to ACM and Call.

webrtc/voice_engine/shared_data.cc

Index: webrtc/voice_engine/shared_data.cc
diff --git a/webrtc/voice_engine/shared_data.cc b/webrtc/voice_engine/shared_data.cc
index ad00e038f673b6f2be01c6d849faf71f410cebbc..403c1f5dbdd1b495f8d9260e7d6e31397fdb9bad 100644
--- a/webrtc/voice_engine/shared_data.cc
+++ b/webrtc/voice_engine/shared_data.cc
@@ -13,6 +13,7 @@
 #include "webrtc/modules/audio_processing/include/audio_processing.h"
 #include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
 #include "webrtc/system_wrappers/interface/trace.h"
+#include "webrtc/video/rtc_event_log.h"
 #include "webrtc/voice_engine/channel.h"
 #include "webrtc/voice_engine/output_mixer.h"
 #include "webrtc/voice_engine/transmit_mixer.h"
@@ -23,16 +24,16 @@ namespace voe {
 
 static int32_t _gInstanceCounter = 0;
 
-SharedData::SharedData(const Config& config) :
-    _instanceId(++_gInstanceCounter),
-    _apiCritPtr(CriticalSectionWrapper::CreateCriticalSection()),
-    _channelManager(_gInstanceCounter, config),
-    _engineStatistics(_gInstanceCounter),
-    _audioDevicePtr(NULL),
-    _moduleProcessThreadPtr(ProcessThread::Create()),
-    _externalRecording(false),
-    _externalPlayout(false)
-{
+SharedData::SharedData(const Config& config)
+    : _instanceId(++_gInstanceCounter),
+      _apiCritPtr(CriticalSectionWrapper::CreateCriticalSection()),
+      _channelManager(_gInstanceCounter, config),
+      _engineStatistics(_gInstanceCounter),
+      _audioDevicePtr(NULL),
+      _moduleProcessThreadPtr(ProcessThread::Create()),
+      _eventLog(RtcEventLog::Create()),

[Henrik Grunell WebRTC, 2015/08/05 09:44:35]

Create the RtcEventLog object when needed, i.e. when the logging is enabled.

[Henrik Grunell WebRTC, 2015/08/07 11:30:03]

Since we keep the Get function in the VoECodec API, create the event log object
at first Get.

[terelius, 2015/08/11 09:04:34]

The idea is that we should be able to log "back in time", i.e. we should be able
to store events that happened before the user enabled logging. I have no idea
when Get is normally called, but creating the logging object at an unspecified
time during the call might cause a failure to log early events.

[Henrik Grunell WebRTC, 2015/08/12 12:38:50]

That would mean that logging is enabled from the start really. What happens when
you "enable logging"? How far back is stored?

[terelius, 2015/08/12 13:05:05]

Poorly explained by me. The event log has an internal buffer which stores the
recent history. The default history is 10 seconds, but it is possible that this
should be increased to 30 seconds or so, depending on what memory usage we get
in real calls.
When the user presses the "Send feedback" button, the recent history is written
to a file and any future events are appended to the same file.

It is important that the event log exists when the ReceiveStreams/SendStreams
(the corresponding audio object is voe, right?) are created since we need to
store configuration information. Without the configuration information we can't
parse the RTP headers.

[ivoc, 2015/08/12 13:16:41]

In the latest version the pointer to RtcEventLog is propagated through the
constructor, so it's hard to avoid initializing the RtcEventLog object within
the constructor as well. 

[Henrik Grunell WebRTC, 2015/08/12 15:29:53]

OK, then it makes sense to create it at start.

+      _externalRecording(false),
+      _externalPlayout(false) {
     Trace::CreateTrace();
     if (OutputMixer::Create(_outputMixerPtr, _gInstanceCounter) == 0)
     {