Enable messages in asserts by default

pkg/analyzer/lib/src/context/context.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.src.context.context;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 264 matching lines @@
         this._options.dart2jsHint != options.dart2jsHint ||
         _notEqual(this._options.errorProcessors, options.errorProcessors) ||
         _notEqual(this._options.excludePatterns, options.excludePatterns) ||
         (this._options.hint && !options.hint) ||
         (this._options.lint && !options.lint) ||
         _notEqual(this._options.lintRules, options.lintRules) ||
         this._options.preserveComments != options.preserveComments ||
         this._options.strongMode != options.strongMode ||
         this._options.enableAssertInitializer !=
             options.enableAssertInitializer ||
-        this._options.enableAssertMessage != options.enableAssertMessage ||
         this._options.enableLazyAssignmentOperators !=
             options.enableLazyAssignmentOperators ||
         ((options is AnalysisOptionsImpl)
             ? this._options.strongModeHints != options.strongModeHints
             : false) ||
         ((options is AnalysisOptionsImpl)
             ? this._options.implicitCasts != options.implicitCasts
             : false) ||
         ((options is AnalysisOptionsImpl)
             ? this._options.nonnullableTypes != options.nonnullableTypes
             : false) ||
         ((options is AnalysisOptionsImpl)
             ? this._options.implicitDynamic != options.implicitDynamic
             : false) ||
         this._options.enableStrictCallChecks !=
             options.enableStrictCallChecks ||
         this._options.enableSuperMixins != options.enableSuperMixins ||
         this._options.patchPlatform != options.patchPlatform;
     this._options.analyzeFunctionBodiesPredicate =
         options.analyzeFunctionBodiesPredicate;
     this._options.generateImplicitErrors = options.generateImplicitErrors;
     this._options.generateSdkErrors = options.generateSdkErrors;
     this._options.dart2jsHint = options.dart2jsHint;
     this._options.enableAssertInitializer = options.enableAssertInitializer;
-    this._options.enableAssertMessage = options.enableAssertMessage;
     this._options.enableStrictCallChecks = options.enableStrictCallChecks;
     this._options.enableLazyAssignmentOperators =
         options.enableLazyAssignmentOperators;
     this._options.enableSuperMixins = options.enableSuperMixins;
     this._options.enableTiming = options.enableTiming;
     this._options.errorProcessors = options.errorProcessors;
     this._options.excludePatterns = options.excludePatterns;
     this._options.hint = options.hint;
     this._options.incremental = options.incremental;
     this._options.incrementalApi = options.incrementalApi;
@@ skipping 1923 matching lines @@
     }
     DartSdk sdk = factory.dartSdk;
     if (sdk == null) {
       throw new ArgumentError(
           "The source factory for an SDK analysis context must have a DartUriResolver");
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }