feat: add support for WebUSB (#36289)

* feat: add support for WebUSB

* fixup for gn check

* fixup gn check on Windows

* Apply review feedback

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* chore: address review feedback

* chore: removed unneeded code

* Migrate non-default ScopedObservation<> instantiations to ScopedObservationTraits<> in chrome/browser/

4016595

Co-authored-by: Charles Kerr <charles@charleskerr.com>

docs/fiddles/features/web-usb/renderer.js

@@ -0,0 +1,33 @@
+function getDeviceDetails(device) {
+  return grantedDevice.productName || `Unknown device ${grantedDevice.deviceId}`
+}
+
+async function testIt() {
+  const noDevicesFoundMsg = 'No devices found'
+  const grantedDevices = await navigator.usb.getDevices()
+  let grantedDeviceList = ''
+  if (grantedDevices.length > 0) {    
+    grantedDevices.forEach(device => {
+      grantedDeviceList += `<hr>${getDeviceDetails(device)}</hr>`
+    })    
+  } else {
+    grantedDeviceList = noDevicesFoundMsg
+  }
+  document.getElementById('granted-devices').innerHTML = grantedDeviceList
+
+  grantedDeviceList = ''
+  try {
+    const grantedDevice = await navigator.usb.requestDevice({
+      filters: []
+    })
+    grantedDeviceList += `<hr>${getDeviceDetails(device)}</hr>`
+    
+  } catch (ex) {
+    if (ex.name === 'NotFoundError') {
+      grantedDeviceList = noDevicesFoundMsg
+    }
+  }
+  document.getElementById('granted-devices2').innerHTML = grantedDeviceList
+}
+
+document.getElementById('clickme').addEventListener('click',testIt)