Add 'containingClassDescription' to HoverInformation.

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 'package:analysis_server/src/protocol.dart' show HoverInformation;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 
@@ skipping 77 matching lines @@
         // 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
+        // containing class
+        ClassElement containingClass =
+            element.getAncestor((e) => e is ClassElement);
+        if (containingClass != null) {
+          hover.containingClassDescription = containingClass.toString();
+        }
+        // containing 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(expression.bestParameterElement);
       // types
       hover.staticType = _safeToString(expression.staticType);
       hover.propagatedType = _safeToString(expression.propagatedType);
       // done
       return hover;
     }
     // not an expression
     return null;
   }
 
   static _safeToString(obj) => obj != null ? obj.toString() : null;
 }