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

An option was added to voe_cmd_test to make a RtcEventLog dump.

BUG=webrtc:4741

Review URL: https://codereview.webrtc.org/1267683002

Cr-Commit-Position: refs/heads/master@{#9901}

webrtc/voice_engine/include/voe_codec.h

@@ -35,6 +35,7 @@
 
 namespace webrtc {
 
+class RtcEventLog;
 class VoiceEngine;
 
 class WEBRTC_DLLEXPORT VoECodec {
@@ -131,6 +132,10 @@ class WEBRTC_DLLEXPORT VoECodec {
   // success, and -1 if failed.
   virtual int SetOpusDtx(int channel, bool enable_dtx) = 0;
 
+  // Get a pointer to the event logging object associated with this Voice
+  // Engine. This pointer will remain valid until VoiceEngine is destroyed.
+  virtual RtcEventLog* GetEventLog() = 0;
+
  protected:
   VoECodec() {}
   virtual ~VoECodec() {}