Add context information to driver and add hooks for plugin management

pkg/analyzer/test/src/task/strong/strong_test_helper.dart

 // Copyright (c) 2015, 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.
 
 // TODO(jmesserly): this file needs to be refactored, it's a port from
 // package:dev_compiler's tests
 library analyzer.test.src.task.strong.strong_test_helper;
 
 import 'dart:async';
 
@@ skipping 290 matching lines @@
       StringBuffer logBuffer = new StringBuffer();
       FileContentOverlay fileContentOverlay = new FileContentOverlay();
       PerformanceLog log = new PerformanceLog(logBuffer);
       AnalysisDriverScheduler scheduler = new AnalysisDriverScheduler(log);
       _driver = new AnalysisDriver(
           scheduler,
           log,
           _resourceProvider,
           new MemoryByteStore(),
           fileContentOverlay,
-          'test',
+          null,
           sourceFactory,
           analysisOptions);
       scheduler.start();
 
       mainUnit = (await _driver.getResult(mainFile.path)).unit;
     } else {
       _context = AnalysisEngine.instance.createAnalysisContext();
       _context.analysisOptions = analysisOptions;
       _context.sourceFactory = sourceFactory;
 
@@ skipping 151 matching lines @@
   @override
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
     if (uri.scheme == 'package') {
       return (provider.getResource(
               provider.convertPath('/packages/' + uri.path)) as File)
           .createSource(uri);
     }
     return super.resolveAbsolute(uri, actualUri);
   }
 }