Add USBDeviceRequestEvent to WebUSB Test API polyfill

This event is fired when the navigator.usb.requestDevice() method is
called and allows us to remove the navigator.usb.test.lastFilters and
navigator.usb.test.chosenDevice attributes which may be more difficult
for other implementations to support.

https: //github.com/WICG/webusb/pull/98
Change-Id: I122b3512f12b68bb36fee6d9e9abc2a4d11c5ea0
Reviewed-on: https://chromium-review.googlesource.com/530091
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Jeffrey Yasskin <jyasskin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490821}

third_party/WebKit/LayoutTests/external/wpt/resources/chromium/webusb-test.js

@@ -379,31 +379,46 @@ class FakeDeviceManager {
   }
 }
 
+class USBDeviceRequestEvent {
+  constructor(deviceFilters, resolve) {
+    this.filters = convertMojoDeviceFilters(deviceFilters);
+    this.resolveFunc_ = resolve;
+  }
+
+  respondWith(value) {
+    // Wait until |value| resolves (if it is a Promise). This function returns
+    // no value.
+    Promise.resolve(value).then(fakeDevice => {
+      let device = internal.deviceManager.devices_.get(fakeDevice);
+      let result = null;
+      if (device) {
+        result = fakeDeviceInitToDeviceInfo(device.guid, device.info);
+      }
+      this.resolveFunc_({ result: result });
+    }, () => {
+      this.resolveFunc_({ result: null });
+    });
+  }
+}
+
 class FakeChooserService {
   constructor() {
     this.bindingSet_ = new mojo.BindingSet(device.mojom.UsbChooserService);
-    this.chosenDevice_ = null;
-    this.lastFilters_ = null;
   }
 
   addBinding(handle) {
     this.bindingSet_.addBinding(this, handle);
   }
 
-  setChosenDevice(fakeDevice) {
-    this.chosenDevice_ = fakeDevice;
-  }
-
   getPermission(deviceFilters) {
-    this.lastFilters_ = convertMojoDeviceFilters(deviceFilters);
-    let device = internal.deviceManager.devices_.get(this.chosenDevice_);
-    if (device) {
-      return Promise.resolve({
-        result: fakeDeviceInitToDeviceInfo(device.guid, device.info)
-      });
-    } else {
-      return Promise.resolve({ result: null });
-    }
+    return new Promise(resolve => {
+      if (navigator.usb.test.onrequestdevice) {
+        navigator.usb.test.onrequestdevice(
+            new USBDeviceRequestEvent(deviceFilters, resolve));
+      } else {
+        resolve({ result: null });
+      }
+    });
   }
 }
 
@@ -438,7 +453,9 @@ class CrossFrameHandleProxy {
 }
 
 class USBTest {
-  constructor() {}
+  constructor() {
+    this.onrequestdevice = undefined;
+  }
 
   initialize() {
     if (internal.initialized)
@@ -499,20 +516,6 @@ class USBTest {
     return fakeDevice;
   }
 
-  set chosenDevice(fakeDevice) {
-    if (!internal.initialized)
-      throw new Error('Call initialize() before setting chosenDevice.');
-
-    internal.chooser.setChosenDevice(fakeDevice);
-  }
-
-  get lastFilters() {
-    if (!internal.initialized)
-      throw new Error('Call initialize() before getting lastFilters.');
-
-    return internal.chooser.lastFilters_;
-  }
-
   reset() {
     if (!internal.initialized)
       throw new Error('Call initialize() before reset().');
@@ -522,7 +525,6 @@ class USBTest {
     return new Promise(resolve => {
       setTimeout(() => {
         internal.deviceManager.removeAllDevices();
-        internal.chooser.setChosenDevice(null);
         resolve();
       }, 0);
     });

third_party/WebKit/LayoutTests/external/wpt/webusb/usb-manual.https.html

@@ -50,7 +50,10 @@ usb_test(() => {
 
 usb_test(() => {
   return getFakeDevice().then(({ device, fakeDevice }) => {
-    navigator.usb.test.chosenDevice = fakeDevice;
+    navigator.usb.test.onrequestdevice = event => {
+      navigator.usb.test.onrequestdevice = undefined;
+      event.respondWith(fakeDevice);
+    }
     return callWithTrustedClick(() => {
       return navigator.usb.requestDevice({ filters: [] }).then(chosenDevice => {
         assert_equals(chosenDevice, device);
@@ -61,7 +64,10 @@ usb_test(() => {
 
 usb_test(() => {
   return getFakeDevice().then(({ device, fakeDevice }) => {
-    navigator.usb.test.chosenDevice = fakeDevice;
+    navigator.usb.test.onrequestdevice = event => {
+      navigator.usb.test.onrequestdevice = undefined;
+      event.respondWith(fakeDevice);
+    }
     return callWithTrustedClick(() => {
       return navigator.usb.requestDevice({ filters: [] }).then(chosenDevice => {
         assert_equals(chosenDevice, device);
@@ -80,6 +86,17 @@ usb_test(() => {
     { vendorId: 5678, productId: 0xF00F }
   ];
 
+  navigator.usb.test.onrequestdevice = event => {
+    navigator.usb.test.onrequestdevice = undefined;
+
+    assert_equals(event.filters.length, expectedFilters.length);
+    for (var i = 0; i < event.filters.length; ++i) {
+      assert_object_equals(event.filters[i], expectedFilters[i]);
+    }
+
+    event.respondWith(null);
+  }
+
   return callWithTrustedClick(() => {
     return navigator.usb.requestDevice({ filters: expectedFilters })
       .then(device => {
@@ -87,10 +104,6 @@ usb_test(() => {
       })
       .catch(error => {
         assert_equals(error.code, DOMException.NOT_FOUND_ERR);
-        let actualFilters = navigator.usb.test.lastFilters;
-        assert_equals(actualFilters.length, expectedFilters.length);
-        for (var i = 0; i < actualFilters.length; ++i)
-          assert_object_equals(actualFilters[i], expectedFilters[i]);
       });
   });
 }, 'filters are sent correctly');