Remove the checker and corresponding dead code

lib/src/analysis_context.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.
 
 library dev_compiler.src.analysis_context;
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_io.dart' show JavaFile;
 import 'package:analyzer/src/generated/sdk_io.dart' show DirectoryBasedDartSdk;
 import 'package:analyzer/src/generated/source.dart' show DartUriResolver;
 import 'package:analyzer/src/generated/source_io.dart';
 
-import '../strong_mode.dart' show StrongModeOptions;
-
-import 'checker/resolver.dart';
 import 'dart_sdk.dart';
 import 'multi_package_resolver.dart';
 import 'options.dart';
 
 /// Creates an [AnalysisContext] with dev_compiler type rules and inference,
 /// using [createSourceFactory] to set up its [SourceFactory].
 AnalysisContext createAnalysisContextWithSources(
-    StrongModeOptions strongOptions, SourceResolverOptions srcOptions,
-    {DartUriResolver sdkResolver, List<UriResolver> fileResolvers}) {
+    SourceResolverOptions srcOptions,
+    {DartUriResolver sdkResolver,
+    List<UriResolver> fileResolvers}) {
   AnalysisEngine.instance.useTaskModel = true;
   var srcFactory = createSourceFactory(srcOptions,
       sdkResolver: sdkResolver, fileResolvers: fileResolvers);
-  return createAnalysisContext(strongOptions)..sourceFactory = srcFactory;
+  return createAnalysisContext()..sourceFactory = srcFactory;
 }
 
 /// Creates an analysis context that contains our restricted typing rules.
-AnalysisContext createAnalysisContext(StrongModeOptions options) {
+AnalysisContext createAnalysisContext() {
   var res = AnalysisEngine.instance.createAnalysisContext();
   res.analysisOptions.strongMode = true;
   return res;
 }
 
-/// Enables dev_compiler inference rules.
-// TODO(jmesserly): is there a cleaner way to plug this in?
-void enableDevCompilerInference(
-    AnalysisContextImpl context, StrongModeOptions options) {
-  context.libraryResolverFactory = (c) =>
-      new LibraryResolverWithInference(c, options);
-}
-
 /// Creates a SourceFactory configured by the [options].
 ///
 /// Use [options.useMockSdk] to specify the SDK mode, or use [sdkResolver]
 /// to entirely override the DartUriResolver.
 ///
 /// If supplied, [fileResolvers] will override the default `file:` and
 /// `package:` URI resolvers.
 SourceFactory createSourceFactory(SourceResolverOptions options,
     {DartUriResolver sdkResolver, List<UriResolver> fileResolvers}) {
   var sdkResolver = options.useMockSdk
@@ skipping 23 matching lines @@
 DartUriResolver createMockSdkResolver(Map<String, String> mockSources) =>
     new MockDartSdk(mockSources, reportMissing: true).resolver;
 
 /// Creates a [DartUriResolver] that uses the SDK at the given [sdkPath].
 DartUriResolver createSdkPathResolver(String sdkPath) {
   var sdk = new DirectoryBasedDartSdk(
       new JavaFile(sdkPath), /*useDart2jsPaths:*/ true);
   sdk.context.analysisOptions.strongMode = true;
   return new DartUriResolver(sdk);
 }