AOT: Add a separate switchable call state for unlinked calls.

runtime/vm/raw_object_snapshot.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
@@ skipping 1525 matching lines @@
 
 
 void RawSingleTargetCache::WriteTo(SnapshotWriter* writer,
                                    intptr_t object_id,
                                    Snapshot::Kind kind,
                                    bool as_reference) {
   UNREACHABLE();
 }
 
 
+RawUnlinkedCall* UnlinkedCall::ReadFrom(SnapshotReader* reader,
+                                        intptr_t object_id,
+                                        intptr_t tags,
+                                        Snapshot::Kind kind,
+                                        bool as_reference) {
+  UNREACHABLE();
+  return UnlinkedCall::null();
+}
+
+
+void RawUnlinkedCall::WriteTo(SnapshotWriter* writer,
+                              intptr_t object_id,
+                              Snapshot::Kind kind,
+                              bool as_reference) {
+  UNREACHABLE();
+}
+
+
 RawICData* ICData::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
                             intptr_t tags,
                             Snapshot::Kind kind,
                             bool as_reference) {
   ASSERT(kind == Snapshot::kScript);
 
   ICData& result = ICData::ZoneHandle(reader->zone(), ICData::New());
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
@@ skipping 1497 matching lines @@
     // We do not allow objects with native fields in an isolate message.
     writer->SetWriteException(Exceptions::kArgument,
                               "Illegal argument in isolate message"
                               " : (object is a UserTag)");
   } else {
     UNREACHABLE();
   }
 }
 
 }  // namespace dart