expose strong checker API, for use by analyzer_cli

lib/src/codegen/js_codegen.dart

Index: lib/src/codegen/js_codegen.dart
diff --git a/lib/src/codegen/js_codegen.dart b/lib/src/codegen/js_codegen.dart
index ea4c24d84ea4039e30af4c544f1335827048cdea..20a1eccf4d49d92187b63aa90a9ec7f991c0259e 100644
--- a/lib/src/codegen/js_codegen.dart
+++ b/lib/src/codegen/js_codegen.dart
@@ -26,7 +26,7 @@ import 'package:dev_compiler/src/js/js_ast.dart' show js;
 import 'package:dev_compiler/devc.dart' show AbstractCompiler;
 import 'package:dev_compiler/src/checker/rules.dart';
 import 'package:dev_compiler/src/info.dart';
-import 'package:dev_compiler/src/options.dart';
+import 'package:dev_compiler/src/options.dart' show CodegenOptions;
 import 'package:dev_compiler/src/utils.dart';
 
 import 'code_generator.dart';
@@ -51,7 +51,7 @@ const DSEND = 'dsend';
 
 class JSCodegenVisitor extends GeneralizingAstVisitor {
   final AbstractCompiler compiler;
-  final CompilerOptions options;
+  final CodegenOptions options;
   final TypeRules rules;
   final LibraryInfo libraryInfo;
 
@@ -99,7 +99,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor {
   JSCodegenVisitor(AbstractCompiler compiler, this.libraryInfo,
       this._extensionTypes, this._fieldsNeedingStorage)
       : compiler = compiler,
-        options = compiler.options,
+        options = compiler.options.codegenOptions,
         rules = compiler.rules,
         root = compiler.entryPointUri {
     _loader = new ModuleItemLoadOrder(_emitModuleItem);