Re-landing of "replace TrySync with Metadata".

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index 7f2afec13f99f7e014e9819bf431eaa134a84195..42c5fdc05549b859cd6b270230d732759cd89eb7 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -7,6 +7,7 @@
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
+#include "vm/exceptions.h"
 #include "vm/globals.h"
 #include "vm/snapshot.h"
 #include "vm/token.h"
@@ -1138,6 +1139,10 @@ class RawCode : public RawObject {
   RawObject* owner_;  // Function, Null, or a Class.
   RawExceptionHandlers* exception_handlers_;
   RawPcDescriptors* pc_descriptors_;
+  union {
+    RawTypedData* catch_entry_state_maps_;
+    RawSmi* variables_;
+  } catch_entry_;
   RawArray* stackmaps_;
   RawArray* inlined_id_to_function_;
   RawCodeSourceMap* code_source_map_;