Generate vmservice_io.dill along with platform.dill.

tools/patch_sdk.dart

Index: tools/patch_sdk.dart
diff --git a/tools/patch_sdk.dart b/tools/patch_sdk.dart
index 64038458e20e667185fccd0c72cc514f3e8ffb32..58ed1232df730b248390389aee43a74709d88a9f 100644
--- a/tools/patch_sdk.dart
+++ b/tools/patch_sdk.dart
@@ -17,7 +17,7 @@ import 'package:analyzer/src/generated/sdk.dart';
 import 'package:path/path.dart' as path;
 
 import 'package:front_end/src/fasta/fasta.dart' as fasta
-    show compilePlatform, writeDepsFile;
+    show compile, compilePlatform, writeDepsFile;
 
 import 'package:compiler/src/kernel/fasta_support.dart' as dart2js
     show compilePlatform;
@@ -109,6 +109,7 @@ Future _main(List<String> argv) async {
 
   Uri platform = outDirUri.resolve('platform.dill.tmp');
   Uri outline = outDirUri.resolve('outline.dill');
+  Uri vmserviceIo = outDirUri.resolve('vmservice_io.dill');
   Uri librariesJson = outDirUri.resolve("lib/libraries.json");
   Uri packages = Uri.base.resolveUri(new Uri.file(packagesFile));
 
@@ -118,6 +119,14 @@ Future _main(List<String> argv) async {
   if (forVm) {
     await fasta.compilePlatform(outDirUri, platform,
         packages: packages, outlineOutput: outline);
+    await fasta.compile([
+      "--sdk=${outDirUri.toString()}",
+      "--platform=${outline.toString()}",
+      "--packages=${packages.toString()}",
+      "dart:vmservice_io",
+      "-o",
+      vmserviceIo.toString()
+    ]);
   } else {
     await dart2js.compilePlatform(outDirUri, platform,
         packages: packages, outlineOutput: outline);