Navigation extension point.

pkg/analysis_server/lib/analysis/navigation/navigation_core.dart

Index: pkg/analysis_server/lib/analysis/navigation/navigation_core.dart
diff --git a/pkg/analysis_server/lib/analysis/navigation/navigation_core.dart b/pkg/analysis_server/lib/analysis/navigation/navigation_core.dart
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index 0000000000000000000000000000000000000000..c708d9a85dc294f10afebbc4a782c80f7edf47e9
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+++ b/pkg/analysis_server/lib/analysis/navigation/navigation_core.dart
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+// Copyright (c) 2015, 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 analysis_server.analysis.navigation.navigation_core;
+
+import 'package:analysis_server/src/protocol.dart'
+    show ElementKind, Location, NavigationRegion, NavigationTarget;
+import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
+import 'package:analyzer/src/generated/source.dart' show Source;
+
+/**
+ * An object used to produce navigation regions.
+ *
+ * Clients are expected to subtype this class when implementing plugins.
+ */
+abstract class NavigationContributor {
+  /**
+   * Contribute navigation regions for a part of the given [source] into the
+   * given [holder]. The part is specified by the [offset] and [length].
+   * The [context] can be used to get analysis results.
+   */
+  void computeNavigation(NavigationHolder holder, AnalysisContext context,
+      Source source, int offset, int length);
+}
+
+/**
+ * An object that [NavigationContributor]s use to record navigation regions
+ * into.
+ *
+ * Clients are not expected to subtype this class.
+ */
+abstract class NavigationHolder {
+  /**
+   * Record a new navigation region with the given [offset] and [length] that
+   * should navigation to the given [targetLocation].
+   */
+  void addRegion(
+      int offset, int length, ElementKind targetKind, Location targetLocation);
+}