Added functions on libjingle API to start and stop the recording of an RtcEventLog.

BUG=webrtc:4741

Review URL: https://codereview.webrtc.org/1374253002

Cr-Commit-Position: refs/heads/master@{#10297}
diff --git a/talk/media/base/fakemediaengine.h b/talk/media/base/fakemediaengine.h
index 57d0145..5a4f46a 100644
--- a/talk/media/base/fakemediaengine.h
+++ b/talk/media/base/fakemediaengine.h
@@ -785,6 +785,10 @@
 
   bool StartAecDump(rtc::PlatformFile file) { return false; }
 
+  bool StartRtcEventLog(rtc::PlatformFile file) { return false; }
+
+  void StopRtcEventLog() {}
+
  private:
   std::vector<FakeVoiceMediaChannel*> channels_;
   std::vector<AudioCodec> codecs_;