Switch CPU profile start/stop markers to monotonic time.

src/api.cc

 // Copyright 2012 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 7066 matching lines @@
 
 
 const CpuProfileNode* CpuProfile::GetSample(int index) const {
   const i::CpuProfile* profile = reinterpret_cast<const i::CpuProfile*>(this);
   return reinterpret_cast<const CpuProfileNode*>(profile->sample(index));
 }
 
 
 int64_t CpuProfile::GetStartTime() const {
   const i::CpuProfile* profile = reinterpret_cast<const i::CpuProfile*>(this);
-  return (profile->start_time() - i::Time::UnixEpoch()).InMicroseconds();
+  return (profile->start_time() - i::TimeTicks()).InMicroseconds();
 }
 
 
 int64_t CpuProfile::GetEndTime() const {
   const i::CpuProfile* profile = reinterpret_cast<const i::CpuProfile*>(this);
-  return (profile->end_time() - i::Time::UnixEpoch()).InMicroseconds();
+  return (profile->end_time() - i::TimeTicks()).InMicroseconds();
 }
 
 
 int CpuProfile::GetSamplesCount() const {
   return reinterpret_cast<const i::CpuProfile*>(this)->samples_count();
 }
 
 
 void CpuProfiler::SetSamplingInterval(int us) {
   ASSERT(us >= 0);
@@ skipping 509 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 } }  // namespace v8::internal