Make TimelineEventBlocks reclaimable

runtime/vm/thread.cc

Index: runtime/vm/thread.cc
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index 79ccec8fa0f1a59a947cf8ec8314f2d2e42b01ec..eff09226730aae79e914661012fe30fbb87aeb2e 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -343,14 +343,6 @@ bool Thread::IsThreadInterrupterEnabled(ThreadInterruptCallback* callback,
 }
 
 
-void Thread::CloseTimelineBlock() {
-  if (timeline_block() != NULL) {
-    timeline_block()->Finish();
-    set_timeline_block(NULL);
-  }
-}
-
-
 bool Thread::CanLoadFromThread(const Object& object) {
 #define CHECK_OBJECT(type_name, member_name, expr, default_init_value)         \
   if (object.raw() == expr) return true;