Add builders for tracing event's structural arguments

cc/scheduler/scheduler_settings.h

Index: cc/scheduler/scheduler_settings.h
diff --git a/cc/scheduler/scheduler_settings.h b/cc/scheduler/scheduler_settings.h
index c282cf6a124573fd99a492fda7298a3bfb9da30f..65d29c8753a97200e9aab8bdfc0df7b054871077 100644
--- a/cc/scheduler/scheduler_settings.h
+++ b/cc/scheduler/scheduler_settings.h
@@ -5,10 +5,16 @@
 #ifndef CC_SCHEDULER_SCHEDULER_SETTINGS_H_
 #define CC_SCHEDULER_SCHEDULER_SETTINGS_H_
 
-#include "base/memory/scoped_ptr.h"
+#include "base/memory/ref_counted.h"
 #include "base/values.h"
 #include "cc/base/cc_export.h"
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace cc {
 class LayerTreeSettings;
 
@@ -27,7 +33,7 @@ class CC_EXPORT SchedulerSettings {
   bool using_synchronous_renderer_compositor;
   bool throttle_frame_production;
 
-  scoped_ptr<base::Value> AsValue() const;
+  scoped_refptr<base::debug::ConvertableToTraceFormat> AsValue() const;
 };
 
 }  // namespace cc