Move the onclose event handler to the FakeUSBDevice object

third_party/WebKit/LayoutTests/usb/resources/webusb-test.js

 'use strict';
 
 // This polyfill library implements the WebUSB Test API as specified here:
 // https://wicg.github.io/webusb/test/
 
 (() => {
 
 // The global mojo object contains the Mojo JS binding modules loaded during
 // initialization.
 let mojo = null;
 
 // These variables are logically members of the USBTest class but are defined
 // here to hide them from being visible as fields of navigator.usb.test.
 let g_initializePromise = null;
 let g_chooserService = null;
 let g_deviceManager = null;
-let g_closeListener = null;
-let g_nextGuid = 0;
 
 function fakeDeviceInitToDeviceInfo(guid, init) {
   let deviceInfo = {
     guid: guid + "",
     usb_version_major: init.usbVersionMajor,
     usb_version_minor: init.usbVersionMinor,
     usb_version_subminor: init.usbVersionSubminor,
     class_code: init.deviceClass,
     subclass_code: init.deviceSubclass,
     protocol_code: init.deviceProtocol,
@@ skipping 313 matching lines @@
     });
     return Promise.resolve({ results: devices });
   }
 
   getDevice(guid, request) {
     let device = this.devicesByGuid_.get(guid);
     if (device) {
       let binding = new mojo.bindings.Binding(
           mojo.device.Device, new FakeDevice(device.info), request);
       binding.setConnectionErrorHandler(() => {
-        if (g_closeListener)
-          g_closeListener(device.fakeDevice);
+        if (device.fakeDevice.onclose)
+          device.fakeDevice.onclose();
       });
       device.bindingArray.push(binding);
     } else {
       request.close();
     }
   }
 
   setClient(client) {
     this.client_ = client;
   }
@@ skipping 23 matching lines @@
         result: fakeDeviceInitToDeviceInfo(device.guid, device.info)
       });
     } else {
       return Promise.resolve({ result: null });
     }
   }
 }
 
 // Unlike FakeDevice this class is exported to callers of USBTest.addFakeDevice.
 class FakeUSBDevice {
+  constructor() {
+    this.onclose = null;

[mcasas, 2017/04/21 02:02:35]

I  think JS initializes all onBla event listeners to null,
if so this is redundant.

[Reilly Grant (use Gerrit), 2017/04/24 19:29:15]

I need to write an actual polyfill EventTarget implementation that implements
both addEventListener and EventHandler attributes correctly. This code just uses
it as a normal attribute so I have to initialize.

+  }
+
   disconnect() {
     setTimeout(() => g_deviceManager.removeDevice(this), 0);
   }
 }
 
 class USBTest {
   constructor() {}
 
   initialize() {
     if (!g_initializePromise) {
@@ skipping 71 matching lines @@
       throw new Error('Call initialize() before addFakeDevice().');
 
     // |addDevice| and |removeDevice| are called in a setTimeout callback so
     // that tests do not rely on the device being immediately available which
     // may not be true for all implementations of this test API.
     let fakeDevice = new FakeUSBDevice();
     setTimeout(() => g_deviceManager.addDevice(fakeDevice, deviceInit), 0);
     return fakeDevice;
   }
 
-  set ondeviceclose(func) {
-    g_closeListener = func;
-  }
-
   set chosenDevice(fakeDevice) {
     if (!g_chooserService)
       throw new Error('Call initialize() before setting chosenDevice.');
 
     g_chooserService.setChosenDevice(fakeDevice);
   }
 
   get lastFilters() {
     if (!g_chooserService)
       throw new Error('Call initialize() before getting lastFilters.');
 
     return g_chooserService.lastFilters_;
   }
 
   reset() {
     if (!g_deviceManager || !g_chooserService)
       throw new Error('Call initialize() before reset().');
 
     g_deviceManager.removeAllDevices();
     g_chooserService.setChosenDevice(null);
-    g_closeListener = null;
   }
 }
 
 navigator.usb.test = new USBTest();
 
 })();