Add KernelToElementMap.getSpannable to avoid most usage of KernelAstAdapter.getNode

pkg/compiler/lib/src/kernel/element_map.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 file.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../common.dart';
 import '../common/names.dart';
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
@@ skipping 130 matching lines @@
   /// Computes the [InterfaceType] referenced by a call to the
   /// [JS_INTERCEPTOR_CONSTANT] function, if any.
   InterfaceType getInterfaceTypeForJsInterceptorCall(ir.StaticInvocation node);
 
   /// Computes the [ConstantValue] for the constant [expression].
   ConstantValue getConstantValue(ir.Expression expression);
 
   /// Returns the `noSuchMethod` [FunctionEntity] call from a
   /// `super.noSuchMethod` invocation within [cls].
   FunctionEntity getSuperNoSuchMethod(ClassEntity cls);
+
+  /// Returns a [Spannable] for a message pointing to the IR [node] in the
+  /// context of [member].
+  Spannable getSpannable(MemberEntity member, ir.Node node);
 }
 
 /// Kinds of foreign functions.
 enum ForeignKind {
   JS,
   JS_BUILTIN,
   JS_EMBEDDED_GLOBAL,
   JS_INTERCEPTOR_CONSTANT,
   NONE,
 }
@@ skipping 760 matching lines @@
   TypeMask getInferredTypeOf(MemberEntity member);
 
   /// Returns the inferred type of a dynamic [selector] access on a receiver of
   /// type [mask].
   TypeMask selectorTypeOf(Selector selector, TypeMask mask);
 
   /// Returns the returned type annotation in the [nativeBehavior].
   TypeMask typeFromNativeBehavior(
       native.NativeBehavior nativeBehavior, ClosedWorld closedWorld);
 }