[profiler] Add CodeEvent entries for RCS counters statically on profiler start.

src/counters.cc

Index: src/counters.cc
diff --git a/src/counters.cc b/src/counters.cc
index 0468d0fbd5b02f39cf4984955a5828db2b03aa73..911cc3d2391f544198c833d736e1cf3943031051 100644
--- a/src/counters.cc
+++ b/src/counters.cc
@@ -324,6 +324,10 @@ const RuntimeCallStats::CounterId RuntimeCallStats::counters[] = {
 };
 
 // static
+const int RuntimeCallStats::counters_count =
+    arraysize(RuntimeCallStats::counters);
+
+// static
 void RuntimeCallStats::Enter(RuntimeCallStats* stats, RuntimeCallTimer* timer,
                              CounterId counter_id) {
   RuntimeCallCounter* counter = &(stats->*counter_id);