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 3ba473fec07d09e5293a836218bba926ba8dcc1b..dd75078bb9b5c79f2d9f1fc7db6a1eebebe96881 100644
--- a/webrtc/call.h
+++ b/webrtc/call.h
@@ -17,6 +17,7 @@
 #include "webrtc/audio_receive_stream.h"
 #include "webrtc/audio_send_stream.h"
 #include "webrtc/audio_state.h"
+#include "webrtc/base/platform_file.h"
 #include "webrtc/base/socket.h"
 #include "webrtc/video_receive_stream.h"
 #include "webrtc/video_send_stream.h"
@@ -142,6 +143,10 @@ class Call {
 
   virtual void OnSentPacket(const rtc::SentPacket& sent_packet) = 0;
 
+  virtual bool StartEventLog(rtc::PlatformFile log_file,
+                             int64_t max_size_bytes) = 0;
+  virtual void StopEventLog() = 0;
+
   virtual ~Call() {}
 };