Add a class to start and stop a Chrome process.

lib/src/util/io.dart

Index: lib/src/util/io.dart
diff --git a/lib/src/util/io.dart b/lib/src/util/io.dart
index 8a4a9036c766984ad7e2b1293decc6960ba3f7bd..1cf51104d023d95657ce5f8037087f3cb2dde4b3 100644
--- a/lib/src/util/io.dart
+++ b/lib/src/util/io.dart
@@ -53,3 +53,20 @@ Future withTempDir(Future fn(String path)) {
         .whenComplete(() => tempDir.deleteSync(recursive: true));
   });
 }
+
+/// Creates a URL string for [address]:[port].
+///
+/// Handles properly formatting IPv6 addresses.
+Uri baseUrlForAddress(InternetAddress address, int port) {
+  if (address.isLoopback) {
+    return new Uri(scheme: "http", host: "localhost", port: port);
+  }
+
+  // IPv6 addresses in URLs need to be enclosed in square brackets to avoid
+  // URL ambiguity with the ":" in the address.
+  if (address.type == InternetAddressType.IP_V6) {
+    return new Uri(scheme: "http", host: "[${address.address}]", port: port);
+  }
+
+  return new Uri(scheme: "http", host: address.address, port: port);
+}