MessageLoop's RUN method will pass a const ref to PendingTask when

base/message_loop.h

Index: base/message_loop.h
===================================================================
--- base/message_loop.h	(revision 180270)
+++ base/message_loop.h	(working copy)
@@ -339,10 +339,10 @@
     TaskObserver();
 
     // This method is called before processing a task.
-    virtual void WillProcessTask(base::TimeTicks time_posted) = 0;
+    virtual void WillProcessTask(const base::PendingTask& pending_task) = 0;
 
     // This method is called after processing a task.
-    virtual void DidProcessTask(base::TimeTicks time_posted) = 0;
+    virtual void DidProcessTask(const base::PendingTask& pending_task) = 0;
 
    protected:
     virtual ~TaskObserver();