Change Process.start to return a future that completes with a

runtime/bin/process_win.cc

Index: runtime/bin/process_win.cc
diff --git a/runtime/bin/process_win.cc b/runtime/bin/process_win.cc
index 331807bb260ee6bd9591c9c3e3c00cf8c8284f8a..104fee3e9eaa1d650717495754e1f98a40ed6421 100644
--- a/runtime/bin/process_win.cc
+++ b/runtime/bin/process_win.cc
@@ -515,10 +515,7 @@ bool Process::Kill(intptr_t id, int signal) {
     return true;  // The process has already died.  Report a successful kill.
   }
   BOOL result = TerminateProcess(process_handle, -1);
-  if (!result) {
-    return false;
-  }
-  return true;
+  return result ? true : false;
 }