Check snapshots for feature compatibility.

runtime/vm/dart.h

 // Copyright (c) 2011, 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_DART_H_
 #define VM_DART_H_
 
 #include "include/dart_api.h"
 #include "vm/allocation.h"
 #include "vm/snapshot.h"
 
 namespace dart {
 
 // Forward declarations.
 class DebugInfo;
 class Isolate;
 class LocalHandle;
 class RawError;
 class ReadOnlyHandles;
 class ThreadPool;
 
 class Dart : public AllStatic {
  public:
-  static const char* InitOnce(
+  static char* InitOnce(
       const uint8_t* vm_isolate_snapshot,
       const uint8_t* instructions_snapshot,
       const uint8_t* data_snapshot,
       Dart_IsolateCreateCallback create,
       Dart_IsolateShutdownCallback shutdown,
       Dart_ThreadExitCallback thread_exit,
       Dart_FileOpenCallback file_open,
       Dart_FileReadCallback file_read,
       Dart_FileWriteCallback file_write,
       Dart_FileCloseCallback file_close,
@@ skipping 19 matching lines @@
     pprof_symbol_generator_ = value;
   }
   static DebugInfo* pprof_symbol_generator() { return pprof_symbol_generator_; }
 
   static LocalHandle* AllocateReadOnlyApiHandle();
   static bool IsReadOnlyApiHandle(Dart_Handle handle);
 
   static uword AllocateReadOnlyHandle();
   static bool IsReadOnlyHandle(uword address);
 
+  static const char* FeaturesString(Snapshot::Kind kind);
+
   static Snapshot::Kind snapshot_kind() {
     return snapshot_kind_;
   }
   static const uint8_t* instructions_snapshot_buffer() {
     return instructions_snapshot_buffer_;
   }
   static void set_instructions_snapshot_buffer(const uint8_t* buffer) {
     instructions_snapshot_buffer_ = buffer;
   }
   static const uint8_t* data_snapshot_buffer() {
@@ skipping 54 matching lines @@
   static Dart_FileOpenCallback file_open_callback_;
   static Dart_FileReadCallback file_read_callback_;
   static Dart_FileWriteCallback file_write_callback_;
   static Dart_FileCloseCallback file_close_callback_;
   static Dart_EntropySource entropy_source_callback_;
 };
 
 }  // namespace dart
 
 #endif  // VM_DART_H_