Add support for assert statements with messages to the analyzer.

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/instrumentation/instrumentation.dart';
@@ skipping 234 matching lines @@
   void set analysisOptions(AnalysisOptions options) {
     bool needsRecompute = this._options.analyzeFunctionBodiesPredicate !=
             options.analyzeFunctionBodiesPredicate ||
         this._options.generateImplicitErrors !=
             options.generateImplicitErrors ||
         this._options.generateSdkErrors != options.generateSdkErrors ||
         this._options.dart2jsHint != options.dart2jsHint ||
         (this._options.hint && !options.hint) ||
         (this._options.lint && !options.lint) ||
         this._options.preserveComments != options.preserveComments ||
+        this._options.enableAssertMessage != options.enableAssertMessage ||
         this._options.enableStrictCallChecks !=
             options.enableStrictCallChecks ||
         this._options.enableSuperMixins != options.enableSuperMixins;
     int cacheSize = options.cacheSize;
     if (this._options.cacheSize != cacheSize) {
       this._options.cacheSize = cacheSize;
     }
     this._options.analyzeFunctionBodiesPredicate =
         options.analyzeFunctionBodiesPredicate;
     this._options.generateImplicitErrors = options.generateImplicitErrors;
     this._options.generateSdkErrors = options.generateSdkErrors;
     this._options.dart2jsHint = options.dart2jsHint;
+    this._options.enableAssertMessage = options.enableAssertMessage;
     this._options.enableStrictCallChecks = options.enableStrictCallChecks;
     this._options.enableSuperMixins = options.enableSuperMixins;
     this._options.hint = options.hint;
     this._options.incremental = options.incremental;
     this._options.incrementalApi = options.incrementalApi;
     this._options.incrementalValidation = options.incrementalValidation;
     this._options.lint = options.lint;
     this._options.preserveComments = options.preserveComments;
     if (needsRecompute) {
       for (WorkManager workManager in workManagers) {
@@ skipping 1817 matching lines @@
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
       scheduleComputation();
     }
     return pendingFuture.future;
   }
 }