Rename the plugin location key and directory name

pkg/analysis_server/lib/src/plugin/plugin_locator.dart

 // Copyright (c) 2017, 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 'package:analyzer/file_system/file_system.dart';
 import 'package:yaml/yaml.dart';
 
 /**
  * An object used to locate a plugin within a package.
  */
 class PluginLocator {
   /**
    * The key used in the `pubspec.yaml` file to specify the location of the
    * analysis plugin.
    */
-  static const String analysisPluginKey = 'analysis_plugin';
+  static const String analyzerPluginKey = 'analyzer_plugin';
 
   /**
    * The name of the default plugin directory, located within the `tools`
    * directory.
    */
-  static const String defaultPluginFolderName = 'analysis_plugin';
+  static const String defaultPluginFolderName = 'analyzer_plugin';
 
   /**
    * The name of the `pubspec.yaml` file.
    */
   static const String pubspecFileName = 'pubspec.yaml';
 
   /**
    * The name of the `tools` directory, in which the default plugin directory is
    * located.
    */
@@ skipping 39 matching lines @@
    */
   String _findPlugin(String packageRoot) {
     Folder packageFolder = resourceProvider.getFolder(packageRoot);
     File pubspecFile = packageFolder.getChildAssumingFile(pubspecFileName);
     if (pubspecFile.exists) {
       try {
         YamlDocument document = loadYamlDocument(pubspecFile.readAsStringSync(),
             sourceUrl: pubspecFile.toUri());
         YamlNode contents = document.contents;
         if (contents is YamlMap) {
-          String pluginPath = contents[analysisPluginKey];
+          String pluginPath = contents[analyzerPluginKey];
           if (pluginPath != null) {
             Folder pluginFolder =
                 packageFolder.getChildAssumingFolder(pluginPath);
             if (pluginFolder.exists) {
               return pluginFolder.path;
             }
           }
         }
       } catch (exception) {
         // If we can't read the file, or if it isn't valid YAML, then ignore it.
       }
     }
     Folder pluginFolder = packageFolder
         .getChildAssumingFolder(toolsFolderName)
         .getChildAssumingFolder(defaultPluginFolderName);
     if (pluginFolder.exists) {
       return pluginFolder.path;
     }
     return null;
   }
 }