Update the analysis server diagnostic page - re-enable code completion and overlay pages,

pkg/analysis_server/lib/src/server/http_server.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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:analysis_server/src/channel/web_socket_channel.dart';
 import 'package:analysis_server/src/socket_server.dart';
+import 'package:analysis_server/src/status/diagnostics.dart';
 import 'package:analysis_server/src/status/get_handler.dart';
-import 'package:analysis_server/src/status/get_handler2.dart';
 
 /**
  * Instances of the class [HttpServer] implement a simple HTTP server. The
  * server:
  *
  * - listens for an UPGRADE request in order to start an analysis server
  * - serves diagnostic information as html pages
  */
 class HttpAnalysisServer {
   /**
@@ skipping 67 matching lines @@
       return null;
     }
   }
 
   /**
    * Handle a GET request received by the HTTP server.
    */
   void _handleGetRequest(HttpRequest request) {
     if (getHandler == null) {
       if (socketServer.analysisServer.options.enableNewAnalysisDriver) {
-        getHandler = new GetHandler2(socketServer, _printBuffer);
+        // TODO(devoncarew): Remove GetHandler2.
+        getHandler = new DiagnosticsSite(socketServer, _printBuffer);
       } else {
+        // TODO(devoncarew): GetHandler is essentially dead code.
         getHandler = new GetHandler(socketServer, _printBuffer);
       }
     }
     getHandler.handleGetRequest(request);
   }
 
   /**
    * Attach a listener to a newly created HTTP server.
    */
   void _handleServer(HttpServer httpServer) {
@@ skipping 28 matching lines @@
    */
   void _returnUnknownRequest(HttpRequest request) {
     HttpResponse response = request.response;
     response.statusCode = HttpStatus.NOT_FOUND;
     response.headers.contentType =
         new ContentType("text", "plain", charset: "utf-8");
     response.write('Not found');
     response.close();
   }
 }
+
+/**
+ * Instances of the class [AbstractGetHandler] handle GET requests.
+ */
+abstract class AbstractGetHandler {
+  /**
+   * Handle a GET request received by the HTTP server.
+   */
+  void handleGetRequest(HttpRequest request);
+}