Add trace code to track all posted tasks in message_loop.

base/debug/trace_event.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Trace events are for tracking application performance.
 //
 // Events are issued against categories. Whereas LOG's
 // categories are statically defined, TRACE categories are created
 // implicitly with a string. For example:
 //   TRACE_EVENT_INSTANT0("MY_SUBSYSTEM", "SomeImportantEvent")
@@ skipping 545 matching lines @@
                                const char* name,
                                const void* id,
                                const char* extra);
   static void AddTraceEventEtw(TraceEventPhase phase,
                                const char* name,
                                const void* id,
                                const std::string& extra);
 
   // Exposed for unittesting:
 
+  // Allows deleting our singleton instance.
+  static void DeleteForTesting();
+
   // Allows resurrecting our singleton instance post-AtExit processing.
   static void Resurrect();
 
   // Allow tests to inspect TraceEvents.
   size_t GetEventsSize() const { return logged_events_.size(); }
   const TraceEvent& GetEventAt(size_t index) const {
     DCHECK(index < logged_events_.size());
     return logged_events_[index];
   }
 
@@ skipping 87 matching lines @@
   Data* p_data_;
   Data data_;
 };
 
 }  // namespace internal
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_TRACE_EVENT_H_