Make browser tests all run from a server instead of the local filesystem.

tools/testing/dart/test_progress.dart

Index: tools/testing/dart/test_progress.dart
diff --git a/tools/testing/dart/test_progress.dart b/tools/testing/dart/test_progress.dart
index 203edbdd195cc33250eaef829dd273bce1f6f720..c74025e8a59461f99eb3535b5944a28786f76dff 100644
--- a/tools/testing/dart/test_progress.dart
+++ b/tools/testing/dart/test_progress.dart
@@ -8,6 +8,7 @@ import "dart:io";
 import "test_runner.dart";
 import "test_suite.dart";
 import "status_file_parser.dart";
+import "http_server.dart" as http_server;
 
 class ProgressIndicator {
   ProgressIndicator(this._startTime, this._printTiming)
@@ -195,6 +196,16 @@ class ProgressIndicator {
       output.add('stderr:');
       output.add(new String.fromCharCodes(test.lastCommandOutput.stderr));
     }
+    if (test is BrowserTestCase) {
+      // Additional command for rerunning the steps locally after the fact.
+      output.add('To retest, run: '
+          '${TestUtils.dartTestExecutable.toNativePath()} '
+          '${TestUtils.dartDir().toNativePath()}/tools/testing/dart/'
+          'http_server.dart -m ${test.configuration["mode"]} '
+          '-a ${test.configuration["arch"]} '
+          '-p ${http_server.TestingServerRunner.serverList[0].port} '
+          '-c ${http_server.TestingServerRunner.serverList[1].port}');
+    }
     for (Command c in test.commands) {
       output.add('');
       String message = (c == test.commands.last