Add FrontEndStrategy, ResolutionFrontEndStrategy and KernelFrontEndStrategy

pkg/compiler/lib/src/frontend_strategy.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 dart2js.frontend_strategy;
+
+import 'common.dart';
+import 'common_elements.dart';
+import 'common/tasks.dart';
+import 'environment.dart';
+import 'library_loader.dart';
+import 'native/resolver.dart';
+import 'serialization/task.dart';
+import 'patch_parser.dart';
+import 'resolved_uri_translator.dart';
+
+/// Strategy pattern that defines the connection between the input format and
+/// the resolved element model.
+abstract class FrontEndStrategy {
+  /// Creates library loader task for this strategy.
+  LibraryLoaderTask createLibraryLoader(
+      ResolvedUriTranslator uriTranslator,
+      ScriptLoader scriptLoader,
+      ElementScanner scriptScanner,
+      LibraryDeserializer deserializer,
+      PatchResolverFunction patchResolverFunc,
+      PatchParserTask patchParser,
+      Environment environment,
+      DiagnosticReporter reporter,
+      Measurer measurer);
+
+  /// Returns the [ElementEnvironment] for the element model used in this
+  /// strategy.
+  ElementEnvironment get elementEnvironment;
+
+  /// Returns the [AnnotationProcessor] for this strategy.
+  AnnotationProcessor get annotationProcesser;
+}