Remove the old task model

pkg/analyzer/lib/src/generated/sdk_io.dart

Index: pkg/analyzer/lib/src/generated/sdk_io.dart
diff --git a/pkg/analyzer/lib/src/generated/sdk_io.dart b/pkg/analyzer/lib/src/generated/sdk_io.dart
index b155b9a784f0d0f9adde775b83fb4843bfb7c4f2..2906943e833f7c6b70a2c9821a94719036ae98f3 100644
--- a/pkg/analyzer/lib/src/generated/sdk_io.dart
+++ b/pkg/analyzer/lib/src/generated/sdk_io.dart
@@ -6,7 +6,7 @@ library engine.sdk.io;
 
 import 'dart:io';
 
-import 'package:analyzer/src/context/context.dart' as newContext;
+import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 
 import 'ast.dart';
@@ -242,11 +242,7 @@ class DirectoryBasedDartSdk implements DartSdk {
   @override
   AnalysisContext get context {
     if (_analysisContext == null) {
-      if (AnalysisEngine.instance.useTaskModel) {
-        _analysisContext = new newContext.SdkAnalysisContext();
-      } else {
-        _analysisContext = new SdkAnalysisContext();
-      }
+      _analysisContext = new SdkAnalysisContext();
       SourceFactory factory = new SourceFactory([new DartUriResolver(this)]);
       _analysisContext.sourceFactory = factory;
       List<String> uris = this.uris;