Implement standalone event tracing in AppRTCDemo.

webrtc/base/event_tracer.h

Index: webrtc/base/event_tracer.h
diff --git a/webrtc/base/event_tracer.h b/webrtc/base/event_tracer.h
index cfc6e9e472ed79c6d0375c739269dca36b361e4f..83cab63dacce21289c251496a7be0b109514bb07 100644
--- a/webrtc/base/event_tracer.h
+++ b/webrtc/base/event_tracer.h
@@ -26,6 +26,8 @@
 #ifndef WEBRTC_BASE_EVENT_TRACER_H_
 #define WEBRTC_BASE_EVENT_TRACER_H_
 
+#include <stdio.h>
+
 namespace webrtc {
 
 typedef const unsigned char* (*GetCategoryEnabledPtr)(const char* name);
@@ -64,6 +66,14 @@ class EventTracer {
       const unsigned char* arg_types,
       const unsigned long long* arg_values,
       unsigned char flags);
+
+  // Set up internal event tracer.
+  static void SetupInternalTracer();

[tommi, 2015/11/24 16:27:09]

would it make sense to move these out of the class and into a namespace, e.g.
webrtc::internal?
or perhaps rtc::tracing::internal?

+  static bool StartInternalCapture(const char* filename);
+  static void StartInternalCaptureToFile(FILE* file);
+  static void StopInternalCapture();
+  // Make sure we run this, this will tear down the internal tracing.
+  static void ShutdownInternalTracer();
 };
 
 }  // namespace webrtc