Add trace code to track all posted tasks in message_loop.

base/tracked_objects.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.
 
 #ifndef BASE_TRACKED_OBJECTS_H_
 #define BASE_TRACKED_OBJECTS_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 328 matching lines @@
 
   void AddDeathSnapshot(const Snapshot& snapshot);
   void AddBirths(const Births& births);
   void AddBirth(const BirthOnThread& birth);
   void AddBirthPlace(const Location& location);
   void Write(std::string* output) const;
   void Clear();
 
  private:
   int birth_count_;
-  std::map<std::string, int> birth_files_;
+  std::map<base::StringPiece, int> birth_files_;
   std::map<Location, int> locations_;
   std::map<const ThreadData*, int> birth_threads_;
   DeathData death_data_;
   std::map<const ThreadData*, int> death_threads_;
 
   DISALLOW_COPY_AND_ASSIGN(Aggregation);
 };
 
 //------------------------------------------------------------------------------
 // Comparator is a class that supports the comparison of Snapshot instances.
@@ skipping 306 matching lines @@
   };
   static State state_;
 
   DISALLOW_COPY_AND_ASSIGN(AutoTracking);
 };
 
 
 }  // namespace tracked_objects
 
 #endif  // BASE_TRACKED_OBJECTS_H_