Gentle start with removing explicit interfaces

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/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/symbols.h"
 #include "vm/visitor.h"
@@ skipping 24 matching lines @@
       (kind == Snapshot::kScript && !RawObject::IsCreatedFromSnapshot(tags))) {
     // Read in the base information.
     intptr_t class_id = reader->ReadIntptrValue();
     bool is_signature_class = reader->Read<bool>();
 
     // Allocate class object of specified kind.
     if (kind == Snapshot::kFull) {
       cls = reader->NewClass(class_id, is_signature_class);
     } else {
       if (class_id < kNumPredefinedCids) {
-        ASSERT((class_id >= kInstanceCid) && (class_id <= kWeakPropertyCid));
+        ASSERT((class_id >= kInstanceCid) && (class_id <= kDartFunctionCid));
         cls = reader->isolate()->class_table()->At(class_id);
       } else {
         if (is_signature_class) {
           cls = New<Closure>(kIllegalCid);
         } else {
           cls = New<Instance>(kIllegalCid);
         }
       }
     }
     reader->AddBackRef(object_id, &cls, kIsDeserialized);
@@ skipping 1966 matching lines @@
                    ptr()->length_,                                             \
                    reinterpret_cast<uint8_t*>(ptr()->external_data_->data())); \
 }                                                                              \
 
 
 BYTEARRAY_TYPE_LIST(EXTERNALARRAY_WRITE_TO)
 #undef BYTEARRAY_WRITE_TO
 #undef BYTEARRAY_TYPE_LIST
 
 
+RawDartFunction* DartFunction::ReadFrom(SnapshotReader* reader,
+                                        intptr_t object_id,
+                                        intptr_t tags,
+                                        Snapshot::Kind kind) {
+  UNREACHABLE();  // DartFunction is an abstract class.
+  return DartFunction::null();
+}
+
+
+void RawDartFunction::WriteTo(SnapshotWriter* writer,
+                              intptr_t object_id,
+                              Snapshot::Kind kind) {
+  UNREACHABLE();  // DartFunction is an abstract class.
+}
+
+
 RawClosure* Closure::ReadFrom(SnapshotReader* reader,
                               intptr_t object_id,
                               intptr_t tags,
                               Snapshot::Kind kind) {
   UNIMPLEMENTED();
   return Closure::null();
 }
 
 
 void RawClosure::WriteTo(SnapshotWriter* writer,
@@ skipping 111 matching lines @@
   // Write out the class and tags information.
   writer->WriteIndexedObject(kWeakPropertyCid);
   writer->WriteIntptrValue(writer->GetObjectTags(this));
 
   // Write out all the other fields.
   writer->Write<RawObject*>(ptr()->key_);
   writer->Write<RawObject*>(ptr()->value_);
 }
 
 }  // namespace dart