diff --git a/pkg/front_end/lib/src/api_prototype/compiler_options.dart b/pkg/front_end/lib/src/api_prototype/compiler_options.dart
index 4e13741..5c0624d 100644
--- a/pkg/front_end/lib/src/api_prototype/compiler_options.dart
+++ b/pkg/front_end/lib/src/api_prototype/compiler_options.dart
@@ -6,18 +6,24 @@
 
 import 'package:kernel/target/targets.dart' show Target;
 
-import 'byte_store.dart';
-import '../base/performance_logger.dart';
+import '../base/performance_logger.dart' show PerformanceLog;
 
 import '../fasta/fasta_codes.dart' show FormattedMessage;
+
 import '../fasta/severity.dart' show Severity;
 
-import 'compilation_message.dart';
-import 'file_system.dart';
-import 'standard_file_system.dart';
+import 'byte_store.dart' show ByteStore, NullByteStore;
+
+import 'compilation_message.dart' show CompilationMessage;
+
+import 'file_system.dart' show FileSystem;
+
+import 'standard_file_system.dart' show StandardFileSystem;
 
 export '../fasta/fasta_codes.dart' show FormattedMessage;
 
+export '../fasta/severity.dart' show Severity;
+
 /// Callback used to report errors encountered during compilation.
 typedef void ErrorHandler(CompilationMessage error);
 
diff --git a/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart b/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
index 81ce898..b7132d0 100644
--- a/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
+++ b/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE.md file.
 
-// TODO(ahe): Copied from closure_conversion branch of kernel, remove this file
-// when closure_conversion is merged with master.
-
 library fasta.testing.kernel_chain;
 
 import 'dart:async' show Future;
@@ -33,14 +30,18 @@
 import 'package:testing/testing.dart'
     show ChainContext, Result, StdioProcess, Step, TestDescription;
 
-import '../../api_prototype/front_end.dart';
+import '../../api_prototype/compilation_message.dart' show CompilationMessage;
+
+import '../../api_prototype/compiler_options.dart' show CompilerOptions;
+
+import '../../api_prototype/kernel_generator.dart' show kernelForProgram;
 
 import '../../base/processed_options.dart' show ProcessedOptions;
 
 import '../../compute_platform_binaries_location.dart'
     show computePlatformBinariesLocation;
 
-import '../compiler_context.dart';
+import '../compiler_context.dart' show CompilerContext;
 
 import '../kernel/verifier.dart' show verifyComponent;
 
diff --git a/pkg/front_end/test/fasta/testing/suite.dart b/pkg/front_end/test/fasta/testing/suite.dart
index 26527d4..02bf15a 100644
--- a/pkg/front_end/test/fasta/testing/suite.dart
+++ b/pkg/front_end/test/fasta/testing/suite.dart
@@ -6,23 +6,20 @@
 
 import 'dart:async' show Future;
 
-import 'dart:io' show File, Platform;
-
 import 'dart:convert' show jsonDecode;
 
-import 'package:front_end/src/api_prototype/standard_file_system.dart'
-    show StandardFileSystem;
-
-import 'package:front_end/src/base/libraries_specification.dart'
-    show TargetLibrariesSpecification;
-
-import 'package:front_end/src/fasta/testing/validating_instrumentation.dart'
-    show ValidatingInstrumentation;
-
-import 'package:front_end/src/fasta/uri_translator_impl.dart';
+import 'dart:io' show File, Platform;
 
 import 'package:kernel/ast.dart' show Library, Component;
 
+import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
+
+import 'package:kernel/core_types.dart' show CoreTypes;
+
+import 'package:kernel/kernel.dart' show loadComponentFromBytes;
+
+import 'package:kernel/target/targets.dart' show TargetFlags;
+
 import 'package:testing/testing.dart'
     show
         Chain,
@@ -34,9 +31,17 @@
         TestDescription,
         StdioProcess;
 
+import 'package:vm/target/vm.dart' show VmTarget;
+
 import 'package:front_end/src/api_prototype/compiler_options.dart'
     show CompilerOptions;
 
+import 'package:front_end/src/api_prototype/standard_file_system.dart'
+    show StandardFileSystem;
+
+import 'package:front_end/src/base/libraries_specification.dart'
+    show TargetLibrariesSpecification;
+
 import 'package:front_end/src/base/processed_options.dart'
     show ProcessedOptions;
 
@@ -48,27 +53,23 @@
 import 'package:front_end/src/fasta/deprecated_problems.dart'
     show deprecated_InputError;
 
+import 'package:front_end/src/fasta/dill/dill_target.dart' show DillTarget;
+
+import 'package:front_end/src/fasta/kernel/kernel_target.dart'
+    show KernelTarget;
+
 import 'package:front_end/src/fasta/testing/kernel_chain.dart'
     show MatchExpectation, Print, TypeCheck, Verify, WriteDill;
 
+import 'package:front_end/src/fasta/testing/validating_instrumentation.dart'
+    show ValidatingInstrumentation;
+
 import 'package:front_end/src/fasta/ticker.dart' show Ticker;
 
 import 'package:front_end/src/fasta/uri_translator.dart' show UriTranslator;
 
-import 'package:front_end/src/fasta/kernel/kernel_target.dart'
-    show KernelTarget;
-
-import 'package:front_end/src/fasta/dill/dill_target.dart' show DillTarget;
-
-import 'package:kernel/kernel.dart' show loadComponentFromBytes;
-
-import 'package:kernel/target/targets.dart' show TargetFlags;
-
-import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
-
-import 'package:kernel/core_types.dart' show CoreTypes;
-
-import 'package:vm/target/vm.dart' show VmTarget;
+import 'package:front_end/src/fasta/uri_translator_impl.dart'
+    show UriTranslatorImpl;
 
 export 'package:testing/testing.dart' show Chain, runMe;