Add native extensions to the Dart shell, on the linux platform.

runtime/bin/dartutils.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 BIN_DARTUTILS_H_
 #define BIN_DARTUTILS_H_
 
 #include "bin/builtin.h"
 #include "include/dart_api.h"
 #include "platform/globals.h"
@@ skipping 50 matching lines @@
   static bool GetBooleanValue(Dart_Handle bool_obj);
   static void SetIntegerInstanceField(Dart_Handle handle,
                                       const char* name,
                                       intptr_t val);
   static intptr_t GetIntegerInstanceField(Dart_Handle handle,
                                           const char* name);
   static void SetStringInstanceField(Dart_Handle handle,
                                      const char* name,
                                      const char* val);
   static bool IsDartSchemeURL(const char* url_name);
+  static bool IsDartExtensionSchemeURL(const char* url_name);
   static bool IsDartIOLibURL(const char* url_name);
   static bool IsDartJsonLibURL(const char* url_name);
   static bool IsDartUriLibURL(const char* url_name);
   static bool IsDartUtf8LibURL(const char* url_name);
   static Dart_Handle CanonicalizeURL(CommandLineOptions* url_mapping,
                                      Dart_Handle library,
                                      const char* url_str);
   static Dart_Handle ReadStringFromFile(const char* filename);
   static Dart_Handle LoadSource(CommandLineOptions* url_mapping,
                                 Dart_Handle library,
                                 Dart_Handle url,
                                 Dart_LibraryTag tag,
                                 const char* filename,
                                 Dart_Handle import_map);
   static bool PostNull(Dart_Port port_id);
   static bool PostInt32(Dart_Port port_id, int32_t value);
 
   static const char* kDartScheme;
+  static const char* kDartExtensionScheme;
   static const char* kBuiltinLibURL;
   static const char* kCoreLibURL;
   static const char* kCoreImplLibURL;
   static const char* kIOLibURL;
   static const char* kJsonLibURL;
   static const char* kUriLibURL;
   static const char* kUtf8LibURL;
 
   static const char* kIdFieldName;
 
@@ skipping 132 matching lines @@
   int Length() const { return cobject_->value.as_array.length; }
   CObject* operator[](int index) const {
     return new CObject(cobject_->value.as_array.values[index]);
   }
   void SetAt(int index, CObject* value) {
     cobject_->value.as_array.values[index] = value->AsApiCObject();
   }
 };
 
 #endif  // BIN_DARTUTILS_H_