webusb: Reject the promise if the device is already open.

content/renderer/usb/web_usb_device_impl.cc

Index: content/renderer/usb/web_usb_device_impl.cc
diff --git a/content/renderer/usb/web_usb_device_impl.cc b/content/renderer/usb/web_usb_device_impl.cc
index b6040a943172efe33292e20ac07e366c34041087..ebb1786f658021710a8ee6389638893d23874818 100644
--- a/content/renderer/usb/web_usb_device_impl.cc
+++ b/content/renderer/usb/web_usb_device_impl.cc
@@ -24,6 +24,7 @@ namespace {
 
 const char kClaimInterfaceFailed[] = "Unable to claim interface.";
 const char kClearHaltFailed[] = "Unable to clear endpoint.";
+const char kDeviceAlreadyOpen[] = "Device has already been opened.";
 const char kDeviceNoAccess[] = "Access denied.";
 const char kDeviceNotConfigured[] = "Device not configured.";
 const char kDeviceUnavailable[] = "Device unavailable.";
@@ -74,6 +75,11 @@ void OnOpenDevice(
           blink::WebUSBError::Error::Security,
           base::ASCIIToUTF16(kDeviceNoAccess)));
       break;
+    case device::usb::OpenDeviceError::ALREADY_OPEN:
+      scoped_callbacks->onError(blink::WebUSBError(
+          blink::WebUSBError::Error::InvalidState,
+          base::ASCIIToUTF16(kDeviceAlreadyOpen)));
+      break;
     default:
       NOTREACHED();
   }