[base] Implement CPU time on Windows.

src/base/cpu.cc

Index: src/base/cpu.cc
diff --git a/src/base/cpu.cc b/src/base/cpu.cc
index 12a38819197a90aa4d91dfbbef86aa64cb1f3455..bd32fb413b0343d39318868f60b3e0e814303cb8 100644
--- a/src/base/cpu.cc
+++ b/src/base/cpu.cc
@@ -338,7 +338,8 @@ CPU::CPU()
       has_vfp_(false),
       has_vfp3_(false),
       has_vfp3_d32_(false),
-      is_fp64_mode_(false) {
+      is_fp64_mode_(false),
+      has_non_stop_time_stamp_counter_(false) {
   memcpy(vendor_, "Unknown", 8);
 #if V8_OS_NACL
 // Portable host shouldn't do feature detection.
@@ -419,6 +420,13 @@ CPU::CPU()
     has_sahf_ = (cpu_info[2] & 0x00000001) != 0;
   }
 
+  // Check if CPU has non stoppable Time Stamp Counter.

[fmeawad, 2016/05/26 16:40:34]

nit: time stamp counter

[lpy, 2016/05/26 20:50:55]

Done.

+  const int parameter_containing_non_stop_time_stamp_counter = 0x80000007;
+  if (num_ext_ids >= parameter_containing_non_stop_time_stamp_counter) {
+    __cpuid(cpu_info, parameter_containing_non_stop_time_stamp_counter);
+    has_non_stop_time_stamp_counter_ = (cpu_info[3] & (1 << 8)) != 0;
+  }
+
 #elif V8_HOST_ARCH_ARM
 
 #if V8_OS_LINUX