Move RtcEventLog object from inside VoiceEngine to Call.

webrtc/call.h

Index: webrtc/call.h
diff --git a/webrtc/call.h b/webrtc/call.h
index 313c5e58c16f49446c8d6fbcdaa92950179628a8..64b99b60afd80e6e2c784204c89f166a3858e721 100644
--- a/webrtc/call.h
+++ b/webrtc/call.h
@@ -24,6 +24,7 @@
 namespace webrtc {
 
 class AudioProcessing;
+class RtcEventLog;
 
 const char* Version();
 
@@ -137,6 +138,11 @@ class Call {
 
   virtual void OnSentPacket(const rtc::SentPacket& sent_packet) = 0;
 
+  // Returns a pointer to the RtcEventLog object, which can be used to start or
+  // stop the log, or to log events. The pointer will remain valid as long as
+  // the Call instance exists.
+  virtual RtcEventLog* RtcEventLog() = 0;
+
   virtual ~Call() {}
 };