Don't recreate CoreTypes in transformers. Pass it in.

pkg/analyzer/lib/src/fasta/analyzer_loader.dart

 // Copyright (c) 2017, 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 fasta.analyzer_loader;
 
 import 'package:front_end/physical_file_system.dart';
 import 'package:kernel/ast.dart' show Program;
 
 import 'package:front_end/src/fasta/builder/builder.dart' show LibraryBuilder;
 
 import 'package:front_end/src/fasta/target_implementation.dart'
     show TargetImplementation;
 
 import 'package:front_end/src/fasta/source/source_class_builder.dart'
     show SourceClassBuilder;
 
 import 'package:front_end/src/fasta/source/source_loader.dart'
     show SourceLoader;
 
 import 'package:analyzer/src/fasta/element_store.dart' show ElementStore;
 
 import 'analyzer_diet_listener.dart' show AnalyzerDietListener;
 
+import 'package:kernel/core_types.dart' show CoreTypes;
+
 class AnalyzerLoader<L> extends SourceLoader<L> {
   ElementStore elementStore;
 
   AnalyzerLoader(TargetImplementation target)
       : super(PhysicalFileSystem.instance, target);
 
   @override
   void computeHierarchy(Program program) {
     elementStore = new ElementStore(coreLibrary, builders);
     ticker.logMs("Built analyzer element model.");
+    coreTypes = new CoreTypes(program);

[ahe, 2017/05/29 14:08:46]

Add:

    ticker.logMs("Computed core types");

[scheglov, 2017/05/30 00:06:10]

I will, but I'm curious what the purpose of this logging.
Given that creating of CoreTypes is very cheap now, and is done lazily, we
neither measure time spent, nor verify that some step is successfully performed.

[ahe, 2017/05/30 09:35:14]

The only way to tell if no time is being spent computing core types is to log
it.

If you don't call the log method, the time (however minuscule) will be
attributed incorrectly to the next phase. So to be able to correctly analyze the
time spent in each phase, it's important that logMs is called at the end of the
phase.

If we don't call log here and someone slows down CoreTypes, we may not notice
it.

You might argue that we can just get those numbers by using the observatory, but
that's not entirely correct. The profiler in the observatory doesn't work well
for measuring short-running programs that may not have been fully optimized yet.

[scheglov, 2017/05/30 16:10:21]

I will not argue with this, you're right Observatory.

OK, now I understand why we need to log here.
Thank you.

   }
 
   @override
   AnalyzerDietListener createDietListener(LibraryBuilder library) {
     return new AnalyzerDietListener(library, elementStore);
   }
 
   @override
   void checkOverrides(List<SourceClassBuilder> sourceClasses) {
     // Not implemented yet. Requires [hierarchy].
   }
 }