Merge pull request #4031 from jtattermusch/win_precise_clock

Use QueryPerformanceCounter as precise clock for windows

src/core/support/time_win32.c

@@ -66,14 +66,12 @@ gpr_timespec gpr_now(gpr_clock_type clock) {
       now_tv.tv_nsec = now_tb.millitm * 1000000;
       break;
     case GPR_CLOCK_MONOTONIC:
+    case GPR_CLOCK_PRECISE:
       QueryPerformanceCounter(&timestamp);
       now_dbl = (timestamp.QuadPart - g_start_time.QuadPart) * g_time_scale;
       now_tv.tv_sec = (time_t)now_dbl;
       now_tv.tv_nsec = (int)((now_dbl - (double)now_tv.tv_sec) * 1e9);
       break;
-    case GPR_CLOCK_PRECISE:
-      gpr_precise_clock_now(&now_tv);
-      break;
   }
   return now_tv;
 }