Enable conditional directives by default.

pkg/analyzer_cli/test/options_test.dart

 // Copyright (c) 2015, 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 analyzer_cli.test.options;
 
 import 'dart:io';
 
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/options.dart';
@@ skipping 14 matching lines @@
         expect(options.buildSummaryInputs, isEmpty);
         expect(options.buildSummaryOnly, isFalse);
         expect(options.buildSummaryOutput, isNull);
         expect(options.buildSuppressExitCode, isFalse);
         expect(options.dartSdkPath, isNotNull);
         expect(options.disableHints, isFalse);
         expect(options.lints, isFalse);
         expect(options.displayVersion, isFalse);
         expect(options.enableStrictCallChecks, isFalse);
         expect(options.enableSuperMixins, isFalse);
-        expect(options.enableConditionalDirectives, isFalse);
         expect(options.enableTypeChecks, isFalse);
         expect(options.hintsAreFatal, isFalse);
         expect(options.ignoreUnrecognizedFlags, isFalse);
         expect(options.log, isFalse);
         expect(options.machineFormat, isFalse);
         expect(options.packageRootPath, isNull);
         expect(options.shouldBatch, isFalse);
         expect(options.showPackageWarnings, isFalse);
         expect(options.showSdkWarnings, isFalse);
         expect(options.sourceFiles, equals(['foo.dart']));
@@ skipping 267 matching lines @@
       'package:p/foo.dart|/path/to/p/lib/foo.dart'
     ]);
     expect(options.buildMode, isTrue);
     expect(options.buildSuppressExitCode, isTrue);
   }
 
   void _parse(List<String> args) {
     options = CommandLineOptions.parse(args);
   }
 }