Add "point of interest" app for command-line testing of dart2js type information.

dart/site/try/poi/poi.dart

+// Copyright (c) 2014, 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 trydart.poi;
+
+import 'dart:async' show
+    Future;
+
+import 'dart:io' show
+    Platform;
+
+import 'package:dart2js_incremental/dart2js_incremental.dart' show
+    reuseCompiler;
+
+import 'package:compiler/implementation/source_file_provider.dart' show
+    FormattingDiagnosticHandler,
+    SourceFileProvider;
+
+import 'package:compiler/compiler.dart' as api show
+    Diagnostic;
+
+Future doneFuture;
+
+void main(List<String> arguments) {
+  Uri script = Uri.base.resolve(arguments.first);
+  int position = int.parse(arguments[1]);
+  FormattingDiagnosticHandler handler = new FormattingDiagnosticHandler();
+  handler
+      ..verbose = true
+      ..enableColors = true;
+
+  Uri libraryRoot = Uri.base.resolve('sdk/');
+  Uri packageRoot = Uri.base.resolveUri(
+      new Uri.file('${Platform.packageRoot}/'));
+
+  var options = [
+      '--analyze-main',
+      '--analyze-only',
+      '--no-source-maps',
+      '--verbose',
+      '--categories=Client,Server',
+  ];
+
+  var cachedCompiler = null;
+  cachedCompiler = reuseCompiler(
+      diagnosticHandler: handler,
+      inputProvider: handler.provider,
+      options: options,
+      cachedCompiler: cachedCompiler,
+      libraryRoot: libraryRoot,
+      packageRoot: packageRoot,
+      packagesAreImmutable: true);
+
+  doneFuture = cachedCompiler.run(script).then((success) {
+    if (success != true) {
+      throw 'Compilation failed';
+    }
+    handler(
+        script, position, position + 1,
+        'Point of interest.', api.Diagnostic.HINT);
+  });
+}