Support deferred library prefix syntax

runtime/vm/raw_object_snapshot.cc

Index: runtime/vm/raw_object_snapshot.cc
===================================================================
--- runtime/vm/raw_object_snapshot.cc	(revision 34312)
+++ runtime/vm/raw_object_snapshot.cc	(working copy)
@@ -1011,6 +1011,7 @@
     library.raw_ptr()->num_anonymous_ = reader->ReadIntptrValue();
     library.raw_ptr()->corelib_imported_ = reader->Read<bool>();
     library.raw_ptr()->debuggable_ = reader->Read<bool>();
+    library.raw_ptr()->deferred_load_ = reader->Read<bool>();
     library.raw_ptr()->load_state_ = reader->Read<int8_t>();
     // The native resolver is not serialized.
     Dart_NativeEntryResolver resolver =
@@ -1060,6 +1061,7 @@
     writer->WriteIntptrValue(ptr()->num_anonymous_);
     writer->Write<bool>(ptr()->corelib_imported_);
     writer->Write<bool>(ptr()->debuggable_);
+    writer->Write<bool>(ptr()->deferred_load_);
     writer->Write<int8_t>(ptr()->load_state_);
     // We do not serialize the native resolver over, this needs to be explicitly
     // set after deserialization.
@@ -1094,6 +1096,8 @@
 
   // Set all non object fields.
   prefix.raw_ptr()->num_imports_ = reader->ReadIntptrValue();
+  prefix.raw_ptr()->is_deferred_load_ = reader->Read<bool>();
+  prefix.raw_ptr()->is_loaded_ = reader->Read<bool>();
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
@@ -1119,11 +1123,13 @@
   writer->WriteInlinedObjectHeader(object_id);
 
   // Write out the class and tags information.
-  writer->WriteVMIsolateObject(kLibraryPrefixCid);
+  writer->WriteIndexedObject(kLibraryPrefixCid);
   writer->WriteIntptrValue(writer->GetObjectTags(this));
 
   // Write out all non object fields.
   writer->WriteIntptrValue(ptr()->num_imports_);
+  writer->Write<bool>(ptr()->is_deferred_load_);
+  writer->Write<bool>(ptr()->is_loaded_);
 
   // Write out all the object pointer fields.
   SnapshotWriterVisitor visitor(writer);