anchor.diff:  
   class PrecompilerCompilerConfiguration extends CompilerConfiguration {
     final String arch;
  -  final bool isProduct;
  -
  -  PrecompilerCompilerConfiguration(
  -      {bool isDebug, bool isChecked, bool isProduct, String arch})
  +
  +  PrecompilerCompilerConfiguration({bool isDebug, bool isChecked, String arch})
         : super._subclass(isDebug: isDebug, isChecked: isChecked),
  -        isProduct = isProduct,
           arch = arch;
   
     int computeTimeoutMultiplier() {
  
positive.code: 
  library compiler_configuration;
  
  import 'dart:io' show Directory, Platform;
  
  import 'runtime_configuration.dart' show RuntimeConfiguration;
  
  
negative.code:       CommandBuilder commandBuilder,
        List arguments,
        Map<String, String> environmentOverrides) {
      var exec = "$buildDir/dart_bootstrap";
      var args = new List();
      args.add("--gen-precompiled-snapshot=$tempDir");
      args.addAll(arguments);
  
      return commandBuilder.getCompilationCommand('precompiler', tempDir, !useSdk,
  