Update HoverInformation to include offset, length, kind.

pkg/analysis_server/lib/src/computer/computer_hover.dart

 // 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 computer.hover;
 
 import 'dart:collection';
 
 import 'package:analysis_server/src/constants.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 53 matching lines @@
   final int _offset;
 
   DartUnitHoverComputer(this._unit, this._offset);
 
   /**
    * Returns the computed hover, maybe `null`.
    */
   Map<String, Object> compute() {
     AstNode node = new NodeLocator.con1(_offset).searchWithin(_unit);
     if (node is Expression) {
-      Hover hover = new Hover();
+      Hover hover = new Hover(node.offset, node.length);
       // element
       Element element = ElementLocator.locateWithOffset(node, _offset);
       if (element != null) {
         // variable, if synthetic accessor
         if (element is PropertyAccessorElement) {
           PropertyAccessorElement accessor = element;
           if (accessor.isSynthetic) {
             element = accessor.variable;
           }
         }
         // description
         hover.elementDescription = element.toString();
+        hover.elementKind = element.kind.displayName;
         // library
         LibraryElement library = element.library;
         if (library != null) {
           hover.containingLibraryName = library.name;
           hover.containingLibraryPath = library.source.fullName;
         }
         // documentation
         String dartDoc = element.computeDocumentationComment();
         dartDoc = _removeDartDocDelimiters(dartDoc);
         hover.dartDoc = dartDoc;
       }
       // parameter
       hover.parameter = _safeToString(node.bestParameterElement);
       // types
       hover.staticType = _safeToString(node.staticType);
       hover.propagatedType = _safeToString(node.propagatedType);
       // done
       return hover.toJson();
     }
     // not an expression
     return null;
   }
 
   static _safeToString(obj) => obj != null ? obj.toString() : null;
 }
 
 
 class Hover {
+  final int offset;
+  final int length;
   String containingLibraryName;
   String containingLibraryPath;
   String dartDoc;
   String elementDescription;
+  String elementKind;
   String parameter;
   String propagatedType;
   String staticType;
 
-  Hover();
+  Hover(this.offset, this.length);
 
   factory Hover.fromJson(Map<String, Object> map) {
-    Hover hover = new Hover();
+    int offset = map[OFFSET];
+    int length = map[LENGTH];
+    Hover hover = new Hover(offset, length);
     hover.containingLibraryName = map[CONTAINING_LIBRARY_NAME];
     hover.containingLibraryPath = map[CONTAINING_LIBRARY_PATH];
     hover.dartDoc = map[DART_DOC];
     hover.elementDescription = map[ELEMENT_DESCRIPTION];
+    hover.elementKind = map[ELEMENT_KIND];
     hover.parameter = map[PARAMETER];
     hover.propagatedType = map[PROPAGATED_TYPE];
     hover.staticType = map[STATIC_TYPE];
     return hover;
   }
 
   Map<String, Object> toJson() {
     Map<String, Object> json = new HashMap<String, Object>();
+    json[OFFSET] = offset;
+    json[LENGTH] = length;
     if (containingLibraryName != null) {
       json[CONTAINING_LIBRARY_NAME] = containingLibraryName;
     }
     if (containingLibraryName != null) {
       json[CONTAINING_LIBRARY_PATH] = containingLibraryPath;
     }
     if (dartDoc != null) {
       json[DART_DOC] = dartDoc;
     }
     if (elementDescription != null) {
       json[ELEMENT_DESCRIPTION] = elementDescription;
     }
+    if (elementKind != null) {
+      json[ELEMENT_KIND] = elementKind;
+    }
     if (parameter != null) {
       json[PARAMETER] = parameter;
     }
     if (propagatedType != null) {
       json[PROPAGATED_TYPE] = propagatedType;
     }
     if (staticType != null) {
       json[STATIC_TYPE] = staticType;
     }
     return json;
   }
 }