Output TimelineEventBlocks in sorted order

runtime/vm/timeline.h

Index: runtime/vm/timeline.h
diff --git a/runtime/vm/timeline.h b/runtime/vm/timeline.h
index 168956a25bb7d0ee9141fa36673cfc97f23d3292..5344f3bf4458bbc8399a5bc14076cf538ae4db76 100644
--- a/runtime/vm/timeline.h
+++ b/runtime/vm/timeline.h
@@ -94,7 +94,6 @@ class TimelineEvent {
   // Keep in sync with StateBits below.
   enum EventType {
     kNone,
-    kSerializedJSON,  // Events from Dart code.
     kBegin,
     kEnd,
     kDuration,
@@ -387,6 +386,10 @@ class TimelineEventScope : public StackResource {
     return enabled_;
   }
 
+  void set_enabled(bool enabled) {
+    enabled_ = enabled;
+  }
+
   const char* label() const {
     return label_;
   }