Support profiling of tasks run as sequenced_tasks

base/tracking_info.cc

Index: base/tracking_info.cc
===================================================================
--- base/tracking_info.cc	(revision 146154)
+++ base/tracking_info.cc	(working copy)
@@ -17,6 +17,10 @@
       delayed_run_time(delayed_run_time) {
 }
 
+TrackingInfo::TrackingInfo()
+    : birth_tally(static_cast<tracked_objects::Births*>(NULL)) {
+}
+
 TrackingInfo::~TrackingInfo() {}
 
 }  // namespace base