Reduce leaking in object tracking tests

base/tracked_objects.h

Index: base/tracked_objects.h
===================================================================
--- base/tracked_objects.h	(revision 107938)
+++ base/tracked_objects.h	(working copy)
@@ -711,12 +711,16 @@
   // the code).
   static TrackedTime Now();
 
-  // WARNING: ONLY call this function when you are running single threaded
-  // (again) and all message loops and threads have terminated.  Until that
-  // point some threads may still attempt to write into our data structures.
-  // Delete recursively all data structures, starting with the list of
+  // Cleans up data structures, and returns statics to near pristine (mostly
+  // uninitialized) state.  If there is any chance that other threads are still
+  // using the data structures, then the |leak| argument should be passed in as
+  // true, and the data structures (birth maps, death maps, ThreadData
+  // insntances, etc.) will be leaked and not deleted.  If you have joined all
+  // threads since the time that InitializeAndSetTrackingStatus() was called,
+  // then you can pass in a |leak| value of false, and this function will
+  // delete recursively all data structures, starting with the list of
   // ThreadData instances.
-  static void ShutdownSingleThreadedCleanup();
+  static void ShutdownSingleThreadedCleanup(bool leak);
 
  private:
   typedef std::stack<const ThreadData*> ThreadDataPool;