Remove references to AnalysisDriver from the plugin mixin classes

pkg/analyzer_plugin/lib/plugin/fix_mixin.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 'dart:async';
 
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/plugin/plugin.dart';
 import 'package:analyzer_plugin/protocol/protocol.dart';
 import 'package:analyzer_plugin/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/src/utilities/fixes/fixes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:analyzer_plugin/utilities/generator.dart';
 
 /**
  * A mixin that can be used when creating a subclass of [ServerPlugin] and
  * mixing in [FixesMixin]. This implements the creation of the fixes request
  * based on the assumption that the driver being created is an [AnalysisDriver].
  *
  * Clients may not extend or implement this class, but are allowed to use it as
  * a mix-in when creating a subclass of [ServerPlugin] that also uses
  * [FixesMixin] as a mix-in.
  */
 abstract class DartFixesMixin implements FixesMixin {
   @override
-  Future<FixesRequest> getFixesRequest(
-      EditGetFixesParams parameters, covariant AnalysisDriver driver) async {
+  Future<FixesRequest> getFixesRequest(EditGetFixesParams parameters) async {
+    String path = parameters.file;
     int offset = parameters.offset;
-    ResolveResult result = await driver.getResult(parameters.file);
+    AnalysisDriver driver = driverForPath(path);
+    if (driver == null) {
+      // Return an error from the request.
+      throw new RequestFailure(
+          RequestErrorFactory.pluginError('Failed to analyze $path', null));
+    }
+    ResolveResult result = await driver.getResult(path);
     return new DartFixesRequestImpl(
         resourceProvider, offset, _getErrors(offset, result), result);
   }
 
   List<AnalysisError> _getErrors(int offset, ResolveResult result) {
     LineInfo lineInfo = result.lineInfo;
     int offsetLine = lineInfo.getLocation(offset).lineNumber;
     return result.errors.where((AnalysisError error) {
       int errorLine = lineInfo.getLocation(error.offset).lineNumber;
       return errorLine == offsetLine;
     }).toList();
   }
 }
 
 /**
  * A mixin that can be used when creating a subclass of [ServerPlugin] to
  * provide most of the implementation for handling fix requests.
  *
  * Clients may not extend or implement this class, but are allowed to use it as
  * a mix-in when creating a subclass of [ServerPlugin].
  */
 abstract class FixesMixin implements ServerPlugin {
   /**
    * Return a list containing the fix contributors that should be used to create
-   * fixes when used in the context of the given analysis [driver].
+   * fixes for the file with the given [path].
    */
-  List<FixContributor> getFixContributors(
-      covariant AnalysisDriverGeneric driver);
+  List<FixContributor> getFixContributors(String path);
 
   /**
    * Return the fixes request that should be passes to the contributors
    * returned from [getFixContributors].
    */
-  Future<FixesRequest> getFixesRequest(
-      EditGetFixesParams parameters, covariant AnalysisDriverGeneric driver);
+  Future<FixesRequest> getFixesRequest(EditGetFixesParams parameters);
 
   @override
   Future<EditGetFixesResult> handleEditGetFixes(
       EditGetFixesParams parameters) async {
     String path = parameters.file;
-    ContextRoot contextRoot = contextRootContaining(path);
-    if (contextRoot == null) {
-      // Return an error from the request.
-      throw new RequestFailure(
-          RequestErrorFactory.pluginError('Failed to analyze $path', null));
-    }
-    AnalysisDriverGeneric driver = driverMap[contextRoot];
-    FixesRequest request = await getFixesRequest(parameters, driver);
-    FixGenerator generator = new FixGenerator(getFixContributors(driver));
+    FixesRequest request = await getFixesRequest(parameters);
+    FixGenerator generator = new FixGenerator(getFixContributors(path));
     GeneratorResult result = await generator.generateFixesResponse(request);
     result.sendNotifications(channel);
     return result.result;
   }
 }