Mojo: Add BindingsSupportImpl on top of HandleWatcher

mojo/common/handle_watcher_unittest.cc

Index: mojo/common/handle_watcher_unittest.cc
diff --git a/mojo/common/handle_watcher_unittest.cc b/mojo/common/handle_watcher_unittest.cc
index ae1a1755ad6f0c5b6a20a62308bdb381df927f3c..e96f7b6c54fcc6c31debeae81580f69343e80909 100644
--- a/mojo/common/handle_watcher_unittest.cc
+++ b/mojo/common/handle_watcher_unittest.cc
@@ -59,7 +59,7 @@ class CallbackHelper {
     run_loop.Run();
   }
 
-  base::Closure GetCallback() {
+  base::Callback<void(MojoResult)> GetCallback() {
     return base::Bind(&CallbackHelper::OnCallback, weak_factory_.GetWeakPtr());
   }
 
@@ -69,7 +69,7 @@ class CallbackHelper {
   }
 
  private:
-  void OnCallback() {
+  void OnCallback(MojoResult result) {
     got_callback_ = true;
     if (run_loop_)
       run_loop_->Quit();