Add optional message to assert in Dart2js.

pkg/compiler/lib/src/typechecker.dart

 // Copyright (c) 2012, 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 dart2js.typechecker;
 
 import 'common/tasks.dart' show
     CompilerTask;
 import 'compiler.dart' show
     Compiler,
@@ skipping 585 matching lines @@
   void pushCascadeType(DartType type) {
     cascadeTypes = cascadeTypes.prepend(type);
   }
 
   DartType popCascadeType() {
     DartType type = cascadeTypes.head;
     cascadeTypes = cascadeTypes.tail;
     return type;
   }
 
+  DartType visitAssert(Assert node) {
+    analyze(node.condition);
+    if (node.hasMessage) analyze(node.message);
+    return const StatementType();
+  }
+
   DartType visitBlock(Block node) {
     return analyze(node.statements);
   }
 
   DartType visitCascade(Cascade node) {
     analyze(node.expression);
     return popCascadeType();
   }
 
   DartType visitCascadeReceiver(CascadeReceiver node) {
@@ skipping 548 matching lines @@
         // This should be the case but we double-check.
         // TODO(johnniwinther): Ensure that we don't suggest malbounded types.
         return shownTypeGeneric;
       }
     }
     return null;
 
   }
 
   DartType visitSend(Send node) {
-    if (elements.isAssert(node)) {
-      return analyzeInvocation(node, const AssertAccess());
-    }
-
     Element element = elements[node];
 
     if (element != null && element.isConstructor) {
       DartType receiverType;
       if (node.receiver != null) {
         receiverType = analyze(node.receiver);
       } else if (node.selector.isSuper()) {
         // TODO(johnniwinther): Lookup super-member in class members.
         receiverType = superType;
       } else {
@@ skipping 739 matching lines @@
 
   visitTypedef(Typedef node) {
     // Do not typecheck [Typedef] nodes.
   }
 
   visitNode(Node node) {
     compiler.internalError(node,
         'Unexpected node ${node.getObjectDescription()} in the type checker.');
   }
 }