Add flag 'implements' to class, it is set anytime someone implements this class. This is a way to r…

runtime/vm/raw_object.h

 // 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.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 421 matching lines @@
     return reinterpret_cast<RawObject**>(&ptr()->allocation_stub_);
   }
 
   cpp_vtable handle_vtable_;
   intptr_t instance_size_;  // Size if fixed length or 0 if variable length.
   intptr_t id_;  // Class Id, also index in the class table.
   intptr_t type_arguments_field_offset_;  // Offset of the type arguments field.
   intptr_t next_field_offset_;  // Offset of the next instance field.
   intptr_t num_native_fields_;  // Number of native fields in class.
   intptr_t token_pos_;
-  uint8_t state_bits_;  // state, is_const, is_interface.
+  uint8_t state_bits_;  // state, is_const, is_interface, is_implemented.
 
   friend class Instance;
   friend class Object;
   friend class RawInstance;
   friend class RawInstructions;
   friend class SnapshotReader;
 };
 
 
 class RawUnresolvedClass : public RawObject {
@@ skipping 1184 matching lines @@
          kExternalUint64ArrayCid == kExternalInt8ArrayCid + 7 &&
          kExternalFloat32ArrayCid == kExternalInt8ArrayCid + 8 &&
          kExternalFloat64ArrayCid == kExternalInt8ArrayCid + 9 &&
          kStacktraceCid == kExternalInt8ArrayCid + 10);
   return (index >= kExternalInt8ArrayCid && index <= kExternalFloat64ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_