Move InheritanceManager to its own file.

pkg/analyzer/lib/src/summary/link.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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 46 matching lines @@
  * - Where possible, we favor method dispatch instead of "is" and "as"
  *   checks.  E.g. see [ReferenceableElementForLink.asConstructor].
  */
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart' show TokenType;
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/constant/value.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/type.dart';
+import 'package:analyzer/src/dart/resolver/inheritance_manager.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/prelink.dart';
 import 'package:analyzer/src/task/strong_mode.dart';
 
 bool isIncrementOrDecrement(UnlinkedExprAssignOperator operator) {
   switch (operator) {
@@ skipping 4270 matching lines @@
       if (type is InterfaceType) {
         Element result = type.lookUpGetter(name, compilationUnit.library);
         result ??= type.lookUpMethod(name, compilationUnit.library);
         return result;
       }
     }
     // TODO(scheglov): implement for propagated types
     return null;
   }
 }