Hooked the trace event argument whitelist up to the background_trace_manager

content/public/browser/background_tracing_manager.h

Index: content/public/browser/background_tracing_manager.h
diff --git a/content/public/browser/background_tracing_manager.h b/content/public/browser/background_tracing_manager.h
index d5e0900f161194badf775087ec0d3bc225de9f24..dd3e3d0a3f1ef81453d77697b3eddc5128b4e5e1 100644
--- a/content/public/browser/background_tracing_manager.h
+++ b/content/public/browser/background_tracing_manager.h
@@ -39,8 +39,8 @@ class BackgroundTracingManager {
   //     );
   // }
   //
-  typedef base::Callback<void(const base::RefCountedString*, base::Closure)>
-      ReceiveCallback;
+  typedef base::Callback<void(const scoped_refptr<base::RefCountedString>&,
+                              base::Closure)> ReceiveCallback;
 
   // Set the triggering rules for when to start recording.
   //
@@ -59,6 +59,7 @@ class BackgroundTracingManager {
   // the manager is idle and a config can be set again.
   virtual bool SetActiveScenario(scoped_ptr<BackgroundTracingConfig> config,
                                  const ReceiveCallback& receive_callback,
+                                 const base::Closure& enabled_callback,
                                  bool requires_anonymized_data) = 0;
 
   // Notifies the caller when the manager is idle (not recording or uploading),