Remove deprecated api from LibraryBuilder.

pkg/front_end/lib/src/fasta/kernel/kernel_procedure_builder.dart

 // Copyright (c) 2016, 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 fasta.kernel_procedure_builder;
 
 import 'package:kernel/ast.dart'
     show
         Arguments,
         AsyncMarker,
@@ skipping 21 matching lines @@
         VariableGet,
         VoidType,
         setParents;
 
 import 'package:kernel/type_algebra.dart' show containsTypeVariable, substitute;
 
 import '../loader.dart' show Loader;
 
 import '../messages.dart'
     show
+        messageConstConstructorWithBody,
+        messageExternalMethodWithBody,
         messageInternalProblemBodyOnAbstractMethod,
         messageNonInstanceTypeVariableUse,
         warning;
 
 import '../problems.dart' show internalProblem;
 
 import '../source/source_library_builder.dart' show SourceLibraryBuilder;
 
 import '../type_inference/type_inference_listener.dart'
     show TypeInferenceListener;
@@ skipping 38 matching lines @@
       : super(metadata, modifiers, returnType, name, typeVariables, formals,
             compilationUnit, charOffset);
 
   void set body(Statement newBody) {
     if (newBody != null) {
       if (isAbstract) {
         return internalProblem(messageInternalProblemBodyOnAbstractMethod,
             newBody.fileOffset, fileUri);
       }
       if (isExternal) {
-        return library.deprecated_addCompileTimeError(
-            newBody.fileOffset, "An external method can't have a body.");
+        return library.addCompileTimeError(
+            messageExternalMethodWithBody, newBody.fileOffset, fileUri);
       }
       if (isConstructor && isConst) {
-        return library.deprecated_addCompileTimeError(
-            newBody.fileOffset, "A const constructor can't have a body.");
+        return library.addCompileTimeError(
+            messageConstConstructorWithBody, newBody.fileOffset, fileUri);
       }
     }
     actualBody = newBody;
     if (function != null) {
       function.body = newBody;
       newBody?.parent = function;
     }
   }
 
   Statement get body => actualBody ??= new EmptyStatement();
@@ skipping 296 matching lines @@
         }
       }
       initializers.add(initializer..parent = constructor);
       initializers.add(superInitializer);
       return;
     }
     initializers.add(initializer);
     initializer.parent = constructor;
   }
 }