Make sky/tools/packager build on Mac

sky/tools/packager/vm.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sky/tools/packager/vm.h"
 
 #include "base/logging.h"
 #include "sky/tools/packager/loader.h"
 #include "sky/tools/packager/logging.h"
 
 namespace blink {
 extern const uint8_t* kDartVmIsolateSnapshotBuffer;
 extern const uint8_t* kDartIsolateSnapshotBuffer;
 }
 
 void InitDartVM() {
   int argc = 0;
   const char** argv = nullptr;
 
   CHECK(Dart_SetVMFlags(argc, argv));
   CHECK(Dart_Initialize(blink::kDartVmIsolateSnapshotBuffer, nullptr, nullptr,
                         nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                         nullptr));
 }
 
 Dart_Isolate CreateDartIsolate() {
   CHECK(blink::kDartIsolateSnapshotBuffer);
   char* error = nullptr;
-  Dart_Isolate isolate = Dart_CreateIsolate("http://example.com", "main",
+  Dart_Isolate isolate = Dart_CreateIsolate("dart:snapshot", "main",
                                             blink::kDartIsolateSnapshotBuffer,
                                             nullptr, nullptr, &error);
 
   CHECK(isolate) << error;
   CHECK(!LogIfError(Dart_SetLibraryTagHandler(HandleLibraryTag)));
   LoadSkyInternals();
 
   Dart_ExitIsolate();
   return isolate;
 }