step 1 in making unittest platform independent.

lib/unittest/unittest_vm.dart

Index: lib/unittest/unittest_vm.dart
diff --git a/lib/unittest/unittest_vm.dart b/lib/unittest/unittest_vm.dart
index b3219398f503fdbcb647559f332d3e92087d4a5a..7d3a0b692473992d3b79e56af9a9b3622095bd47 100644
--- a/lib/unittest/unittest_vm.dart
+++ b/lib/unittest/unittest_vm.dart
@@ -8,21 +8,10 @@
 #library('unittest');
 
 #import('dart:io');
-#source('shared.dart');
-
-_platformInitialize() {
-  // Do nothing.
-}
-
-_platformDefer(void callback()) {
-  new Timer(0, (timer) {
-    callback();
-  });
-}
+#import('dart:isolate');
 
-_platformStartTests() {
-  // Do nothing.
-}
+#source('config.dart');
+#source('shared.dart');
 
 _platformCompleteTests(int testsPassed, int testsFailed, int testsErrors) {
   // Print each test's result.
@@ -52,3 +41,11 @@ _platformCompleteTests(int testsPassed, int testsFailed, int testsErrors) {
   // A non-zero exit code is used by the test infrastructure to detect failure.
   if (!success) exit(1);
 }
+
+Configuration _defaultConfig() {
+  return new Configuration(
+      () {}, // do nothing onInit
+      () {}, // do nothing onStart
+      (testCase) {}, // do nothing onTestResult
+      _platformCompleteTests);
+}