Remove use of unstable box syntax.

http://www.robohornet.org gives a score of 101.36 on master,
and 102.68 with this PR. The latter is slightly better,
but probably within noise level.
So it looks like this PR does not affect DOM performance.

This is expected since `Box::new` is defined as:

```rust
impl<T> Box<T> {
    #[inline(always)]
    pub fn new(x: T) -> Box<T> {
        box x
    }
}
```

With inlining, it should compile to the same as box syntax.

1 files changed, 3 insertions, 3 deletions

diff --git a/components/script/dom/bluetooth.rs b/components/script/dom/bluetooth.rs
index ac3b9b7ea53..7da30e027cd 100644
--- a/components/script/dom/bluetooth.rs
+++ b/components/script/dom/bluetooth.rs
@@ -132,7 +132,7 @@ impl Bluetooth {
     }
 
     pub fn new(global: &GlobalScope) -> DomRoot<Bluetooth> {
-        reflect_dom_object(box Bluetooth::new_inherited(),
+        reflect_dom_object(Box::new(Bluetooth::new_inherited()),
                            global,
                            BluetoothBinding::Wrap)
     }
@@ -224,7 +224,7 @@ pub fn response_async<T: AsyncBluetoothListener + DomObject + 'static>(
         promise: Some(TrustedPromise::new(promise.clone())),
         receiver: Trusted::new(receiver),
     }));
-    ROUTER.add_route(action_receiver.to_opaque(), box move |message| {
+    ROUTER.add_route(action_receiver.to_opaque(), Box::new(move |message| {
         struct ListenerTask<T: AsyncBluetoothListener + DomObject> {
             context: Arc<Mutex<BluetoothContext<T>>>,
             action: BluetoothResponseResult,
@@ -249,7 +249,7 @@ pub fn response_async<T: AsyncBluetoothListener + DomObject + 'static>(
         if let Err(err) = result {
             warn!("failed to deliver network data: {:?}", err);
         }
-    });
+    }));
     action_sender
 }