Tweak public APIs and use them in patch_sdk, dart2js, and kernel-service

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

Index: pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
diff --git a/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart b/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
index b78ac35fb1de46a5c65c5cd551266042d1ea5ec6..4b1ca3273197de89fd8042b5761aa4a4f8f9d674 100644
--- a/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
+++ b/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:io';
 
 import 'package:front_end/file_system.dart';
 import 'package:front_end/incremental_kernel_generator.dart';
@@ -13,27 +12,17 @@ import 'package:front_end/src/base/processed_options.dart';
 import 'package:front_end/src/fasta/dill/dill_library_builder.dart';
 import 'package:front_end/src/fasta/dill/dill_target.dart';
 import 'package:front_end/src/fasta/kernel/kernel_target.dart';
+import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:front_end/src/fasta/ticker.dart';
 import 'package:front_end/src/fasta/translate_uri.dart';
 import 'package:front_end/src/incremental/byte_store.dart';
 import 'package:front_end/src/incremental/file_state.dart';
 import 'package:kernel/binary/ast_from_binary.dart';
-import 'package:kernel/binary/limited_ast_to_binary.dart';
 import 'package:kernel/kernel.dart' hide Source;
 import 'package:kernel/target/targets.dart' show TargetFlags;
 import 'package:kernel/target/vm_fasta.dart' show VmFastaTarget;
 import 'package:meta/meta.dart';
 
-class ByteSink implements Sink<List<int>> {
-  final BytesBuilder builder = new BytesBuilder();
-
-  void add(List<int> data) {
-    builder.add(data);
-  }
-
-  void close() {}
-}
-
 /// Implementation of [IncrementalKernelGenerator].
 ///
 /// TODO(scheglov) Update the documentation.
@@ -268,7 +257,8 @@ class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
 
       _logger.run('Serialize ${kernelLibraries.length} libraries', () {
         program.uriToSource.clear();
-        List<int> bytes = _writeProgramBytes(program, kernelLibraries.contains);
+        List<int> bytes =
+            serializeProgram(program, filter: kernelLibraries.contains);
         _byteStore.put(kernelKey, bytes);
         _logger.writeln('Stored ${bytes.length} bytes.');
       });
@@ -374,12 +364,6 @@ class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
       }
     });
   }
-
-  List<int> _writeProgramBytes(Program program, bool filter(Library library)) {
-    ByteSink byteSink = new ByteSink();
-    new LimitedBinaryPrinter(byteSink, filter).writeProgramFile(program);
-    return byteSink.builder.takeBytes();
-  }
 }
 
 /// Compilation result for a library cycle.