Add optional message to assert in Dart2js.

pkg/compiler/lib/src/resolution/semantic_visitor.dart

Index: pkg/compiler/lib/src/resolution/semantic_visitor.dart
diff --git a/pkg/compiler/lib/src/resolution/semantic_visitor.dart b/pkg/compiler/lib/src/resolution/semantic_visitor.dart
index 6ef3a4bbf21363ea60a27fb7ffc2b1e6c375a48b..8e50bbed1c68427849cec16d8944da7ec7ddb98a 100644
--- a/pkg/compiler/lib/src/resolution/semantic_visitor.dart
+++ b/pkg/compiler/lib/src/resolution/semantic_visitor.dart
@@ -1297,32 +1297,6 @@ abstract class SemanticSendVisitor<R, A> {
       Node rhs,
       A arg);
 
-  /// Call to `assert` with [expression] as the condition.
-  ///
-  /// For instance:
-  ///
-  ///     m() { assert(expression); }
-  ///
-  R visitAssert(
-      Send node,
-      Node expression,
-      A arg);
-
-  /// Call to `assert` with the wrong number of [arguments].
-  ///
-  /// For instance:
-  ///
-  ///     m() { assert(); }
-  ///
-  /// or
-  ///
-  ///     m() { assert(expression1, expression2); }
-  ///
-  R errorInvalidAssert(
-      Send node,
-      NodeList arguments,
-      A arg);
-
   /// Binary expression `left operator right` where [operator] is a user
   /// definable operator. Binary expressions using operator `==` are handled
   /// by [visitEquals] and index operations `a[b]` are handled by [visitIndex].