Move the onclose event handler to the FakeUSBDevice object

third_party/WebKit/LayoutTests/usb/usbDevice-iframe.html

Index: third_party/WebKit/LayoutTests/usb/usbDevice-iframe.html
diff --git a/third_party/WebKit/LayoutTests/usb/usbDevice-iframe.html b/third_party/WebKit/LayoutTests/usb/usbDevice-iframe.html
index b6514072106d3b1b10da023a877cb1fe70a3c2ac..2ccead73c49787c816c251c38d4c60eb698ca9bc 100644
--- a/third_party/WebKit/LayoutTests/usb/usbDevice-iframe.html
+++ b/third_party/WebKit/LayoutTests/usb/usbDevice-iframe.html
@@ -11,7 +11,6 @@ function runIframeDisconnectTest(onDeviceConnected) {
   return navigator.usb.test.initialize().then(() => {
     return new Promise((resolve, reject) => {
       let opened = false;
-      let fakeDevice = null;
 
       let iframe = document.createElement('iframe');
       iframe.src = 'resources/open-in-iframe.html';
@@ -23,7 +22,11 @@ function runIframeDisconnectTest(onDeviceConnected) {
 
       window.onmessage = messageEvent => {
         if (messageEvent.data == 'Ready') {
-          fakeDevice = navigator.usb.test.addFakeDevice(fakeDeviceInit);
+          let fakeDevice = navigator.usb.test.addFakeDevice(fakeDeviceInit);
+          fakeDevice.onclose = () => {
+            assert_true(opened);
+            resolve();
+          };
         } else if (messageEvent.data == 'Success') {
           opened = true;
           onDeviceConnected(iframe);
@@ -32,12 +35,6 @@ function runIframeDisconnectTest(onDeviceConnected) {
         }
       };
 
-      navigator.usb.test.ondeviceclose = closedFakeDevice => {
-        assert_equals(closedFakeDevice, fakeDevice);
-        assert_true(opened);
-        resolve();
-      };
-
       document.body.appendChild(iframe);
     });
   });