isolates refactor: this change introduces 'dart:isolate' as a library. This is a

runtime/vm/custom_isolate_test.cc

 // 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.
 
 #include "include/dart_api.h"
 
 #include "vm/unit_test.h"
 
 // Custom Isolate Test.
 //
 // This mid-size test uses the Dart Embedding Api to create a custom
 // isolate abstraction.  Instead of having a dedicated thread for each
 // isolate, as is the case normally, this implementation shares a
 // single thread among the isolates using an event queue.
 
 namespace dart {
 
 // Only ia32 and x64 can run execution tests.
 #if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64)
 
 static void native_echo(Dart_NativeArguments args);
 static void CustomIsolateImpl_start(Dart_NativeArguments args);
 static Dart_NativeFunction NativeLookup(Dart_Handle name, int argc);
 
 
 static const char* kCustomIsolateScriptChars =
+    "#import('dart:isolate');\n"
+    "\n"
     "class GlobalsHack {\n"
     "  static ReceivePort _receivePort;\n"
     "}\n"
     "\n"
     "ReceivePort get receivePort() {\n"
     "  return GlobalsHack._receivePort;\n"
     "}\n"
     "\n"
     "echo(arg) native \"native_echo\";\n"
     "\n"
@@ skipping 318 matching lines @@
   OS::Print("-- Finished event loop --\n");
   EXPECT_STREQ("Received: 43", saved_echo);
   free(const_cast<char*>(saved_echo));
 
   delete event_queue;
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart