feat(benchmarks): Add basic dart transformer benchmarks.

Adds simple benchmarks for various transformation phases, as well as hello_world.
Does not integrate these into any benchmark frameworks yet.

modules/angular2/test/benchmark/transform/integration/hello_world.dart

@@ -0,0 +1,84 @@
+library angular2.benchmark.transform.integration.hello_world;
+
+import 'dart:async';
+import 'package:angular2/src/transform/common/options.dart';
+import 'package:angular2/src/transform/transformer.dart';
+import 'package:barback/barback.dart';
+import 'package:code_transformers/benchmarks.dart';
+import 'package:unittest/unittest.dart';
+
+Future main() => runBenchmark();
+
+allTests() {
+  test('Hello World Benchmark Runs', runBenchmark);
+}
+
+Future runBenchmark() async {
+  var options = new TransformerOptions(['index.dart']);
+  var files = {
+    new AssetId('a', 'web/index.dart'): indexContents,
+    new AssetId('a', 'web/index_common.dart'): indexCommonContents,
+  };
+  var benchmark = new TransformerBenchmark(
+      new AngularTransformerGroup(options).phases, files);
+  print('\nRunning hello_world benchmark...');
+  var result = await benchmark.measure();
+  print('Done, took ${result.round()}μs on average.');
+}
+
+const indexContents = '''
+library examples.src.hello_world.index;
+
+import "index_common.dart" as app;
+import "package:angular2/src/reflection/reflection.dart" show reflector;
+import "package:angular2/src/reflection/reflection_capabilities.dart"
+    show ReflectionCapabilities;
+
+main() {
+  reflector.reflectionCapabilities = new ReflectionCapabilities();
+  app.main();
+}
+''';
+
+const indexCommonContents = '''
+library examples.src.hello_world.index_common;
+
+import "package:angular2/angular2.dart"
+    show bootstrap, Component, Decorator, Template, NgElement;
+import "package:angular2/di.dart" show Injectable;
+
+@Component(selector: "hello-app", services: const [GreetingService])
+@Template(
+    inline: '<div class="greeting">{{greeting}} <span red>world</span>!</div>'
+        '<button class="changeButton" (click)="changeGreeting()">'
+        'change greeting</button><content></content>',
+    directives: const [RedDec])
+class HelloCmp {
+  String greeting;
+  HelloCmp(GreetingService service) {
+    this.greeting = service.greeting;
+  }
+  changeGreeting() {
+    this.greeting = "howdy";
+  }
+}
+
+@Decorator(selector: "[red]")
+class RedDec {
+  RedDec(NgElement el) {
+    el.domElement.style.color = "red";
+  }
+}
+
+@Injectable()
+class GreetingService {
+  String greeting;
+  GreetingService() {
+    this.greeting = "hello";
+  }
+}
+
+main() {
+  bootstrap(HelloCmp);
+}
+''';