Create an app snapshot of the Dart front end.

utils/kernel-service/kernel-service.dart

 // Copyright (c) 2016, 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.
 
 // This is an interface to the Dart Kernel parser and Kernel binary generator.
 // It is used by the kernel-isolate to load Dart source code and generate
 // Kernel binary format.
 
 import 'dart:isolate';
 import 'dart:async';
@@ skipping 74 matching lines @@
   try {
     result = await parseScript(scriptUri, packagesUri.path, patchedSdk.path);
   } catch (error) {
     tag = -tag; // Mark reply as an exception.
     result = error.toString();
   }
 
   port.send([tag, inputFileUrl, inputFileUrl, null, result]);
 }
 
-main() => new RawReceivePort()..handler = _processLoadRequest;
+// This entry point is used when running in the kernel isolate.
+start() => new RawReceivePort()..handler = _processLoadRequest;
+
+// This entry point is used when creating an app snapshot. The argument provides
+// a script to compile to warm-up generated code.
+main(args) {
+  var tag = 1;
+  var scriptUri = args[0];
+  var responsePort = new RawReceivePort();
+  responsePort.handler = (response) {
+    if (response[0] == tag) {
+      // Success.
+      responsePort.close();
+    } else if (response[0] == -tag) {
+      // Compilation error.
+      throw response[4];
+    } else {
+      throw "Unexpected response: $response";
+    }
+  };
+  var request = [tag, responsePort.sendPort, scriptUri];
+  _processLoadRequest(request);
+}