Add support for building patched_sdk and platform.dill for dart2js:

pkg/front_end/lib/src/fasta/kernel/kernel_target.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.
 
 library fasta.kernel_target;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show File, IOSink;
 
@@ skipping 73 matching lines @@
         LibraryBuilder,
         MemberBuilder,
         MixinApplicationBuilder,
         NamedMixinApplicationBuilder,
         NamedTypeBuilder,
         TypeBuilder,
         TypeVariableBuilder;
 
 import 'verifier.dart' show verifyProgram;
 
 class KernelTarget extends TargetImplementation {

[ahe, 2017/04/27 11:48:31]

Would it make sense to have two subclasses of this: one for the Dart VM, and one
for dart2js?

Ideally we can avoid having the word "dart2js" in Fasta, and we can avoid
importing anything from package:compiler into fasta. Instead, package:compiler
would be able to import from Fasta.

[Siggi Cherem (dart-lang), 2017/04/28 21:37:20]

Done. Thanks for the suggestion. I made the change in this direction, but
eventually I'd like to shift to pass options and get rid of the subclasses.

There should be no reference to dart2js in fasta anymore

   final bool strongMode;
 
   final DillTarget dillTarget;
 
   /// Shared with [CompilerContext].
   final Map<String, Source> uriToSource;
 
   SourceLoader<Library> loader;
   Program program;
 
   final List errors = [];
 
   final TypeBuilder dynamicType =
       new KernelNamedTypeBuilder("dynamic", null, -1, null);
 
-  KernelTarget(
-      DillTarget dillTarget, TranslateUri uriTranslator, this.strongMode,
+  KernelTarget(DillTarget dillTarget, TranslateUri uriTranslator,
+      this.strongMode, bool forDart2js,
       [Map<String, Source> uriToSource])
       : dillTarget = dillTarget,
         uriToSource = uriToSource ?? CompilerContext.current.uriToSource,
-        super(dillTarget.ticker, uriTranslator) {
+        super(dillTarget.ticker, uriTranslator, forDart2js) {
     resetCrashReporting();
     loader = createLoader();
   }
 
   void addError(file, int charOffset, String message) {
     Uri uri = file is String ? Uri.parse(file) : file;
     InputError error = new InputError(uri, charOffset, message);
     print(error.format());
     errors.add(error);
   }
@@ skipping 137 matching lines @@
       {bool dumpIr: false, bool verify: false}) async {
     if (loader.first == null) return null;
     if (errors.isNotEmpty) {
       return handleInputError(uri, null, isFullProgram: true);
     }
     try {
       await loader.buildBodies();
       loader.finishStaticInvocations();
       finishAllConstructors();
       loader.finishNativeMethods();
-      transformMixinApplications();
-      // TODO(ahe): Don't call this from two different places.
-      setup_builtin_library.transformProgram(program);
-      otherTransformations();
+      if (forVm) {
+        transformMixinApplications();
+        // TODO(ahe): Don't call this from two different places.
+        setup_builtin_library.transformProgram(program);
+        otherTransformations();
+      }
       if (dumpIr) this.dumpIr();
       if (verify) this.verify();
       errors.addAll(loader.collectCompileTimeErrors().map((e) => e.format()));
       if (errors.isNotEmpty) {
         return handleInputError(uri, null, isFullProgram: true);
       }
       if (uri == null) return program;
       return await writeLinkedProgram(uri, program, isFullProgram: true);
     } on InputError catch (e) {
       return handleInputError(uri, e, isFullProgram: true);
@@ skipping 94 matching lines @@
     // that used when there's no fileUri on an element. Instead, ensure all
     // elements have a fileUri.
     uriToSource[""] = new Source(<int>[0], const <int>[]);
     Program program = new Program(libraries, uriToSource);
     if (loader.first != null) {
       Builder builder = loader.first.lookup("main", -1, null);
       if (builder is KernelProcedureBuilder) {
         program.mainMethod = builder.procedure;
       }
     }
-    if (errors.isEmpty || dillTarget.isLoaded) {
+    if (forVm && (errors.isEmpty || dillTarget.isLoaded)) {
       setup_builtin_library.transformProgram(program);
     }
     ticker.logMs("Linked program");
     return program;
   }
 
   Future<Program> writeLinkedProgram(Uri uri, Program program,
       {bool isFullProgram}) async {
     File output = new File.fromUri(uri);
     IOSink sink = output.openWrite();
@@ skipping 315 matching lines @@
   }
   for (Constructor constructor in superclass.constructors) {
     if (constructor.name.name.isEmpty) {
       return constructor.function.requiredParameterCount == 0
           ? constructor
           : null;
     }
   }
   return null;
 }