Outline of how to factor out compiler and runtime specifics.

dart/tools/testing/dart/runtime_configuration.dart

Index: dart/tools/testing/dart/runtime_configuration.dart
diff --git a/dart/tools/testing/dart/runtime_configuration.dart b/dart/tools/testing/dart/runtime_configuration.dart
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+++ b/dart/tools/testing/dart/runtime_configuration.dart
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+// 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 compiler_configuration;
+
+// TODO(ahe): I expect this class will become abstract very soon.
+class RuntimeConfiguration {
+  // TODO(ahe): Remove this constructor and move the switch to
+  // test_options.dart.  We probably want to store an instance of
+  // [RuntimeConfiguration] in [configuration] there.
+  factory RuntimeConfiguration(Map configuration) {
+    String runtime = configuration['runtime'];
+    switch (runtime) {
+      case 'ContentShellOnAndroid':
+      case 'DartiumOnAndroid':
+      case 'chrome':
+      case 'chromeOnAndroid':
+      case 'd8':
+      case 'dartium':
+      case 'ff':
+      case 'firefox':
+      case 'ie10':
+      case 'ie9':
+      case 'jsshell':
+      case 'none':
+      case 'opera':
+      case 'safari':
+      case 'vm':
+        return new RuntimeConfiguration._subclass();
+      case 'drt':
+        return new DrtRuntimeConfiguration();
+      default:
+        throw "Unknown runtime '$runtime'";
+    }
+  }
+
+  RuntimeConfiguration._subclass();
+
+  int computeTimeoutMultiplier({
+      bool isDebug: false,
+      bool isChecked: false,
+      String arch}) {
+    int multiplier = 1;
+    switch (arch) {
+      case 'simarm':
+      case 'arm':
+      case 'simmips':
+      case 'mips':
+        multiplier *= 4;
+        break;
+    }
+    if (isDebug) {
+      multiplier *= 2;
+    }
+    return multiplier;
+  }
+}
+
+class DrtRuntimeConfiguration extends RuntimeConfiguration {
+  DrtRuntimeConfiguration()
+      : super._subclass();
+
+  int computeTimeoutMultiplier({
+      bool isDebug: false,
+      bool isChecked: false,
+      String arch}) {
+    return 4 // Allow additional time for browser testing to run.
+        * super.computeTimeoutMultiplier(
+            isDebug: isDebug, isChecked: isChecked);
+  }
+}