Add more safe points in compiler

runtime/vm/pages.cc

Index: runtime/vm/pages.cc
diff --git a/runtime/vm/pages.cc b/runtime/vm/pages.cc
index 9768bc5f2510fad9045046e9a9564144c5968753..40c9c06883141fed0ae6aac3fa608a51e4f81a3b 100644
--- a/runtime/vm/pages.cc
+++ b/runtime/vm/pages.cc
@@ -849,6 +849,8 @@ void PageSpace::MarkSweep(bool invoke_api_callbacks) {
   Isolate* isolate = heap_->isolate();
   ASSERT(isolate == Isolate::Current());
 
+  const int64_t pre_safe_point = OS::GetCurrentMonotonicMicros();
+
   // Wait for pending tasks to complete and then account for the driver task.
   {
     MonitorLocker locker(tasks_lock());
@@ -991,6 +993,7 @@ void PageSpace::MarkSweep(bool invoke_api_callbacks) {
     page_space_controller_.EvaluateGarbageCollection(
         usage_before, GetCurrentUsage(), start, end);
 
+    heap_->RecordTime(kSafePoint, start - pre_safe_point);
     heap_->RecordTime(kMarkObjects, mid1 - start);
     heap_->RecordTime(kResetFreeLists, mid2 - mid1);
     heap_->RecordTime(kSweepPages, mid3 - mid2);