feat(dart/transform): Add quick_transformer

Add an implementation of the transformer which runs only the phases
which replace `Asset`s, rather than generate them.

Closes #5484

modules_dart/transform/lib/src/transform/quick_transformer.dart

@@ -0,0 +1,68 @@
+library angular2.src.transform.quick_transformer;
+
+import 'package:barback/barback.dart';
+import 'package:dart_style/dart_style.dart';
+
+import 'common/formatter.dart' as formatter;
+import 'common/options.dart';
+import 'common/options_reader.dart';
+import 'deferred_rewriter/transformer.dart';
+// import 'directive_metadata_linker/transformer.dart';
+// import 'directive_processor/transformer.dart';
+import 'inliner_for_test/transformer.dart';
+import 'reflection_remover/transformer.dart';
+// import 'stylesheet_compiler/transformer.dart';
+// import 'template_compiler/transformer.dart';
+
+export 'common/options.dart';
+
+/// Replaces Angular 2 mirror use with generated code.
+///
+/// Typical users should not use this implementation and should instead use
+/// package:angular2/transformer.dart.
+///
+/// This alternative excludes phases that generate new [Asset]s, including only
+/// the phases that replace existing [Asset]s.
+///
+/// This can be used if all code that would be generated already exists as real
+/// files, rather than needing to be generated by [Transformer]s.
+class AngularTransformerGroup extends TransformerGroup {
+  AngularTransformerGroup._(phases, {bool formatCode: false}) : super(phases) {
+    if (formatCode) {
+      formatter.init(new DartFormatter());
+    }
+  }
+
+  factory AngularTransformerGroup(TransformerOptions options) {
+    var phases;
+    if (options.inlineViews) {
+      phases = [
+        [new InlinerForTest(options)]
+      ];
+    } else {
+      // Only the phases that replace [Asset]s.
+      phases = [
+        [new ReflectionRemover(options)],
+        [new DeferredRewriter(options)],
+      ];
+      /*
+      phases = [
+        [new DirectiveProcessor(options)],
+        [new DirectiveMetadataLinker()],
+        [new ReflectionRemover(options)],
+        [
+          new DeferredRewriter(options),
+          new StylesheetCompiler(),
+          new TemplateCompiler(options)
+        ],
+      ];
+      */
+    }
+    return new AngularTransformerGroup._(phases,
+        formatCode: options.formatCode);
+  }
+
+  factory AngularTransformerGroup.asPlugin(BarbackSettings settings) {
+    return new AngularTransformerGroup(parseBarbackSettings(settings));
+  }
+}