Switch CPU profile start/stop markers to monotonic time.

src/profile-generator.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 190 matching lines @@
   // Add pc -> ... -> main() call path to the profile.
   void AddPath(const Vector<CodeEntry*>& path);
   void CalculateTotalTicksAndSamplingRate();
 
   const char* title() const { return title_; }
   const ProfileTree* top_down() const { return &top_down_; }
 
   int samples_count() const { return samples_.length(); }
   ProfileNode* sample(int index) const { return samples_.at(index); }
 
-  Time start_time() const { return start_time_; }
-  Time end_time() const { return end_time_; }
+  TimeTicks start_time() const { return start_time_; }
+  TimeTicks end_time() const { return end_time_; }
 
   void UpdateTicksScale();
 
   void Print();
 
  private:
   const char* title_;
   bool record_samples_;
-  Time start_time_;
-  Time end_time_;
-  ElapsedTimer timer_;
+  TimeTicks start_time_;
+  TimeTicks end_time_;
   List<ProfileNode*> samples_;
   ProfileTree top_down_;
 
   DISALLOW_COPY_AND_ASSIGN(CpuProfile);
 };
 
 
 class CodeMap {
  public:
   CodeMap() : next_shared_id_(1) { }
@@ skipping 116 matching lines @@
   CodeEntry* gc_entry_;
   CodeEntry* unresolved_entry_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileGenerator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROFILE_GENERATOR_H_