Package-ify Dromaeo and browser controller functionality

samples/third_party/dromaeo/lib/transformer.dart

Index: samples/third_party/dromaeo/lib/transformer.dart
diff --git a/samples/third_party/dromaeo/lib/transformer.dart b/samples/third_party/dromaeo/lib/transformer.dart
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index 0000000000000000000000000000000000000000..88fb58485fdd0040d3ed427a19fe0bde0c0fffeb
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+++ b/samples/third_party/dromaeo/lib/transformer.dart
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+library dromaeo.transformer;
+
+import 'dart:async';
+import 'package:barback/barback.dart';
+
+/// Transformer used by `pub build` and `pub serve` to rewrite dromaeo html
+/// files to run performance tests.
+class DromaeoTransformer extends Transformer {
+
+  final BarbackSettings settings;
+
+  DromaeoTransformer.asPlugin(this.settings);
+
+  /// The index.html file and the tests/dom-*-html.html files are the ones we
+  /// apply this transform to.
+  Future<bool> isPrimary(Asset asset) {
+    var reg = new RegExp('(tests/dom-.+-html\.html\$)|(index\.html\$)');
+    return new Future.value(reg.hasMatch(asset.id.path));
+  }
+
+  Future apply(Transform transform) {
+    Asset primaryAsset = transform.primaryInput;
+    AssetId primaryAssetId = primaryAsset.id;
+
+    return primaryAsset.readAsString().then((String fileContents) {
+      var filename = primaryAssetId.toString();
+      var outputFileContents = fileContents;
+
+      if (filename.endsWith('index.html')) {
+        var index = outputFileContents.indexOf(
+            '<script src="packages/browser/dart.js">');
+        outputFileContents = outputFileContents.substring(0, index) +
+            '<script src="packages/browser_controller' +
+            '/perf_test_controller.js"></script>\n' +
+            outputFileContents.substring(index);
+        transform.addOutput(new Asset.fromString(new AssetId.parse(
+            primaryAssetId.toString().replaceAll('.html', '-dart.html')),
+            outputFileContents));
+      }
+
+      outputFileContents = _sourceJsNotDart(outputFileContents);
+      // Rename the script to take the JavaScript source.
+      transform.addOutput(new Asset.fromString(new AssetId.parse(
+          _appendJs(primaryAssetId.toString())),
+          outputFileContents));
+    });
+  }
+
+  String _appendJs(String path) => path.replaceAll('.html', '-js.html');
+
+  /// Given an html file that sources a Dart file, rewrite the html to instead
+  /// source the compiled JavaScript file.
+  String _sourceJsNotDart(String fileContents) {
+    var dartScript = new RegExp(
+        '<script type="application/dart" src="([\\w-]+)\.dart">');
+    var match = dartScript.firstMatch(fileContents);
+    return fileContents.replaceAll(dartScript, '<script type="text/javascript"'
+        ' src="${match.group(1)+ ".dart.js"}" defer>');
+  }
+}