Add builders for tracing event's structural arguments

cc/scheduler/delay_based_time_source.h

Index: cc/scheduler/delay_based_time_source.h
diff --git a/cc/scheduler/delay_based_time_source.h b/cc/scheduler/delay_based_time_source.h
index 18c8002f2925b746461572c5e31a12526d5ad8d4..e503bdf920fef14e1d413e12cb6a814f8e9c40a4 100644
--- a/cc/scheduler/delay_based_time_source.h
+++ b/cc/scheduler/delay_based_time_source.h
@@ -11,7 +11,12 @@
 #include "base/values.h"
 #include "cc/base/cc_export.h"
 
-namespace base { class SingleThreadTaskRunner; }
+namespace base {
+namespace debug {
+class TracedValue;
+}
+class SingleThreadTaskRunner;
+}
 
 namespace cc {
 
@@ -49,7 +54,7 @@ class CC_EXPORT DelayBasedTimeSource
   // Virtual for testing.
   virtual base::TimeTicks Now() const;
 
-  virtual scoped_ptr<base::Value> AsValue() const;
+  virtual void AsValueInto(base::debug::TracedValue* dict) const;
 
  protected:
   DelayBasedTimeSource(base::TimeDelta interval,