Implement type inference for asserts in constructor initializers.

pkg/front_end/lib/src/fasta/type_inference/type_inference_listener.dart

 // Copyright (c) 2017, 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.md file.
 
 import 'package:front_end/src/fasta/type_inference/type_inference_engine.dart';
 import 'package:kernel/ast.dart';
 
 /// Base class for [TypeInferenceListener] that defines the API for debugging.
 ///
 /// By default no debug info is printed.  To enable debug printing, mix in
@@ skipping 72 matching lines @@
 /// "with TypeInferenceDebugging" clause below.
 class TypeInferenceListener
     extends TypeInferenceBase // with TypeInferenceDebugging
 {
   bool asExpressionEnter(AsExpression expression, DartType typeContext) =>
       genericExpressionEnter("asExpression", expression, typeContext);
 
   void asExpressionExit(AsExpression expression, DartType inferredType) =>
       genericExpressionExit("asExpression", expression, inferredType);
 
+  void assertInitializerEnter(LocalInitializer initializer) =>
+      genericInitializerEnter("assertInitializer", initializer);
+
+  void assertInitializerExit(LocalInitializer initializer) =>
+      genericInitializerExit("assertInitializer", initializer);
+
   void assertStatementEnter(AssertStatement statement) =>
       genericStatementEnter('assertStatement', statement);
 
   void assertStatementExit(AssertStatement statement) =>
       genericStatementExit('assertStatement', statement);
 
   bool awaitExpressionEnter(AwaitExpression expression, DartType typeContext) =>
       genericExpressionEnter("awaitExpression", expression, typeContext);
 
   void awaitExpressionExit(AwaitExpression expression, DartType inferredType) =>
@@ skipping 332 matching lines @@
 
   void whileStatementExit(WhileStatement statement) =>
       genericStatementExit("whileStatement", statement);
 
   void yieldStatementEnter(YieldStatement statement) =>
       genericStatementEnter('yieldStatement', statement);
 
   void yieldStatementExit(YieldStatement statement) =>
       genericStatementExit('yieldStatement', statement);
 }