Change the process API to be completely asynchronous.

tests/standalone/src/ProcessExitNegativeTest.dart

Index: tests/standalone/src/ProcessExitNegativeTest.dart
diff --git a/tests/standalone/src/ProcessExitNegativeTest.dart b/tests/standalone/src/ProcessExitNegativeTest.dart
index 2209f82832447717dd56d8fdaf64d00846922189..f07c0747b4efc686973f6b7531320be935e93212 100644
--- a/tests/standalone/src/ProcessExitNegativeTest.dart
+++ b/tests/standalone/src/ProcessExitNegativeTest.dart
@@ -6,10 +6,9 @@
 // exit handler is reported correctly.
 
 void main() {
-  Process p = new Process("true", []);
+  Process p = new Process.start("true", []);
   p.exitHandler = (int s) {
     print(a.toString());  // Should cause a compilation error here.
     p.close();
   };
-  p.start();
 }