Add Chromium-style TimeDelta, Time and TimeTicks classes, and a new ElapsedTimer class.

src/optimizing-compiler-thread.h

Index: src/optimizing-compiler-thread.h
diff --git a/src/optimizing-compiler-thread.h b/src/optimizing-compiler-thread.h
index aff94eddc22429b0aeadd05f830e515d7e544eb4..80e7f6fc47a5b2d162599991e3b80c2f18d14e43 100644
--- a/src/optimizing-compiler-thread.h
+++ b/src/optimizing-compiler-thread.h
@@ -32,6 +32,7 @@
 #include "flags.h"
 #include "platform.h"
 #include "unbound-queue-inl.h"
+#include "time/time.h"
 
 namespace v8 {
 namespace internal {
@@ -51,9 +52,7 @@ class OptimizingCompilerThread : public Thread {
       isolate_(isolate),
       stop_semaphore_(OS::CreateSemaphore(0)),
       input_queue_semaphore_(OS::CreateSemaphore(0)),
-      install_mutex_(OS::CreateMutex()),
-      time_spent_compiling_(0),
-      time_spent_total_(0) {
+      install_mutex_(OS::CreateMutex()) {
     NoBarrier_Store(&stop_thread_, static_cast<AtomicWord>(CONTINUE));
     NoBarrier_Store(&queue_length_, static_cast<AtomicWord>(0));
   }
@@ -112,8 +111,8 @@ class OptimizingCompilerThread : public Thread {
   Mutex* install_mutex_;
   volatile AtomicWord stop_thread_;
   volatile Atomic32 queue_length_;
-  int64_t time_spent_compiling_;
-  int64_t time_spent_total_;
+  TimeDelta time_spent_compiling_;
+  TimeDelta time_spent_total_;
 };
 
 } }  // namespace v8::internal