extract InheritedReferenceContributor from imported reference contributor

pkg/analysis_server/lib/src/services/completion/dart/inherited_reference_contributor.dart

Index: pkg/analysis_server/lib/src/services/completion/dart/inherited_reference_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/inherited_reference_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/inherited_reference_contributor.dart
new file mode 100644
index 0000000000000000000000000000000000000000..646f6ee47714fa0a0c0b6e72f48baa5a6e71354f
--- /dev/null
+++ b/pkg/analysis_server/lib/src/services/completion/dart/inherited_reference_contributor.dart
@@ -0,0 +1,105 @@
+// Copyright (c) 2014, 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 services.completion.contributor.dart.inherited_ref;
+
+import 'dart:async';
+
+import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
+import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
+import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
+import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
+import 'package:analysis_server/src/services/completion/optype.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+
+import '../../../protocol_server.dart'
+    show CompletionSuggestion, CompletionSuggestionKind;
+import 'package:analyzer/src/generated/resolver.dart';
+
+/**
+ * A contributor for calculating suggestions for inherited references.
+ */
+class InheritedReferenceContributor extends DartCompletionContributor
+    with ElementSuggestionBuilder {
+  @override
+  LibraryElement containingLibrary;
+
+  @override
+  CompletionSuggestionKind kind;
+
+  @override
+  Future<List<CompletionSuggestion>> computeSuggestions(
+      DartCompletionRequest request) async {
+    if (!request.includeIdentifiers) {
+      return EMPTY_LIST;
+    }
+    ClassDeclaration classDecl = _enclosingClass(request.target);
+    if (classDecl == null || classDecl.element == null) {
+      return EMPTY_LIST;
+    }
+
+    containingLibrary = request.libraryElement;
+    bool isFunctionalArgument = request.target.isFunctionalArgument();
+    kind = isFunctionalArgument
+        ? CompletionSuggestionKind.IDENTIFIER
+        : CompletionSuggestionKind.INVOCATION;
+    OpType optype = (request as DartCompletionRequestImpl).opType;
+    for (InterfaceType type in classDecl.element.allSupertypes) {
+      if (!isFunctionalArgument) {
+        for (PropertyAccessorElement elem in type.accessors) {
+          if (elem.isGetter) {
+            if (optype.includeReturnValueSuggestions) {
+              addSuggestion(elem);
+            }
+          } else {
+            if (optype.includeVoidReturnSuggestions) {
+              addSuggestion(elem);
+            }
+          }
+        }
+      }
+      for (MethodElement elem in type.methods) {
+        if (elem.returnType == null) {
+          addSuggestion(elem);
+        } else if (!elem.returnType.isVoid) {
+          if (optype.includeReturnValueSuggestions) {
+            addSuggestion(elem);
+          }
+        } else {
+          if (optype.includeVoidReturnSuggestions) {
+            addSuggestion(elem);
+          }
+        }
+      }
+    }
+    return suggestions;
+  }
+}
+
+/**
+ * Return the class containing the target
+ * or `null` if the target is in a static method or field
+ * or not in a class.
+ */
+ClassDeclaration _enclosingClass(CompletionTarget target) {
+  AstNode node = target.containingNode;
+  while (node != null) {
+    if (node is ClassDeclaration) {
+      return node;
+    }
+    if (node is MethodDeclaration) {
+      if (node.isStatic) {
+        return null;
+      }
+    }
+    if (node is FieldDeclaration) {
+      if (node.isStatic) {
+        return null;
+      }
+    }
+    node = node.parent;
+  }
+  return null;
+}