Add timestamps to CPU profile samples.

src/sampler.cc

 // Copyright 2013 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 571 matching lines @@
 Mutex* SamplerThread::mutex_ = NULL;
 SamplerThread* SamplerThread::instance_ = NULL;
 
 
 //
 // StackTracer implementation
 //
 DISABLE_ASAN void TickSample::Init(Isolate* isolate,
                                    const RegisterState& regs) {
   ASSERT(isolate->IsInitialized());
+  timestamp = TimeTicks::HighResolutionNow();
   pc = regs.pc;
   state = isolate->current_vm_state();
 
   // Avoid collecting traces while doing GC.
   if (state == GC) return;
 
   Address js_entry_sp = isolate->js_entry_sp();
   if (js_entry_sp == 0) {
     // Not executing JS now.
     return;
@@ skipping 148 matching lines @@
 #endif  // USE_SIMULATOR
     SampleStack(state);
   }
   ResumeThread(profiled_thread);
 }
 
 #endif  // USE_SIGNALS
 
 
 } }  // namespace v8::internal