Thread::Stop() must be called before any subclass's destructor completes.

webkit/appcache/appcache_update_job_unittest.cc

Index: webkit/appcache/appcache_update_job_unittest.cc
diff --git a/webkit/appcache/appcache_update_job_unittest.cc b/webkit/appcache/appcache_update_job_unittest.cc
index 7fade2e682ff257fd7377550eaad4727796ba5d9..0739cda7d52a924f38c115c1d4a3e6e31b07988c 100644
--- a/webkit/appcache/appcache_update_job_unittest.cc
+++ b/webkit/appcache/appcache_update_job_unittest.cc
@@ -514,8 +514,6 @@ class IOThread : public base::Thread {
   }
 
   ~IOThread() {
-    // We cannot rely on our base class to stop the thread since we want our
-    // CleanUp function to run.
     Stop();
   }