time: Add a static TimeTicks method that returns the underlying clock

base/time/time_win.cc

Index: base/time/time_win.cc
diff --git a/base/time/time_win.cc b/base/time/time_win.cc
index dc968ad63980edbbe0280519a654447c121a74ae..59d4de6c535fcec566f6766dd09ab2fe88b3a51e 100644
--- a/base/time/time_win.cc
+++ b/base/time/time_win.cc
@@ -512,6 +512,12 @@ bool TimeTicks::IsHighResolution() {
 }
 
 // static
+TimeTicks::Clock TimeTicks::GetClock() {
+  return IsHighResolution() ?
+      Clock::WIN_QPC : Clock::WIN_ROLLOVER_PROTECTED_TIME_GET_TIME;
+}
+
+// static
 ThreadTicks ThreadTicks::Now() {
   DCHECK(IsSupported());