Decode the Dart message into a Dart_CMessage structure before calling the native port callback

runtime/vm/dart_api_impl.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_API_IMPL_H_
 #define VM_DART_API_IMPL_H_
 
 #include "vm/allocation.h"
 #include "vm/object.h"
 
@@ skipping 103 matching lines @@
   static Dart_Handle True();
 
   // Gets a handle to False
   static Dart_Handle False();
 
   // Allocates space in the local zone.
   static uword Allocate(intptr_t size);
 
   // Reallocates space in the local zone.
   static uword Reallocate(uword ptr, intptr_t old_size, intptr_t new_size);
+
+  // Performs one-time initialization needed by the API.
+  static void InitOnce();
+
+ private:
+  // Thread local key used by the API. Currently holds the current
+  // ApiNativeScope if any.
+  static ThreadLocalKey api_native_key_;
+
+  friend class ApiNativeScope;
 };
 
 class IsolateSaver {
  public:
   explicit IsolateSaver(Isolate* current_isolate)
       : saved_isolate_(current_isolate) {
   }
   ~IsolateSaver() {
     Isolate::SetCurrent(saved_isolate_);
   }
  private:
   Isolate* saved_isolate_;
 
   DISALLOW_COPY_AND_ASSIGN(IsolateSaver);
 };
 
 }  // namespace dart.
 
 #endif  // VM_DART_API_IMPL_H_