Move the wire protocol support into the public API

pkg/analysis_server/lib/src/computer/computer_highlights2.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.highlights2;
 
-import 'package:analysis_server/src/protocol.dart' hide Element;
+import 'package:analysis_server/plugin/protocol/protocol.dart' hide Element;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 
 /**
  * A computer for [HighlightRegion]s in a Dart [CompilationUnit].
  */
 class DartUnitHighlightsComputer2 {
   final CompilationUnit _unit;
 
@@ skipping 791 matching lines @@
   void _addRegions_functionBody(FunctionBody node) {
     Token keyword = node.keyword;
     if (keyword != null) {
       Token star = node.star;
       int offset = keyword.offset;
       int end = star != null ? star.end : keyword.end;
       computer._addRegion(offset, end - offset, HighlightRegionType.BUILT_IN);
     }
   }
 }