Add onconnect and ondisconnect events to navigator.usb.

Source/modules/webusb/USB.h

Index: Source/modules/webusb/USB.h
diff --git a/Source/modules/webusb/USB.h b/Source/modules/webusb/USB.h
index 7a5cb00d5dd4885fb0535cd063b8dd609fb02be5..5d2d60ca1894b3c65f34f596865955afa2d624f1 100644
--- a/Source/modules/webusb/USB.h
+++ b/Source/modules/webusb/USB.h
@@ -7,6 +7,7 @@
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptWrappable.h"
+#include "core/events/EventTarget.h"
 #include "modules/webusb/USBController.h"
 #include "platform/heap/Handle.h"
 
@@ -17,9 +18,10 @@ class ScriptState;
 class USBDeviceRequestOptions;
 
 class USB final
-    : public GarbageCollectedFinalized<USB>
-    , public ScriptWrappable {
+    : public RefCountedGarbageCollectedEventTargetWithInlineData<USB> {
     DEFINE_WRAPPERTYPEINFO();
+    REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(USB);
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(USB);
 public:
     static USB* create(LocalFrame& frame)
     {
@@ -28,8 +30,15 @@ public:
 
     explicit USB(LocalFrame& frame);
 
+    // USB.idl
     ScriptPromise getDevices(ScriptState*);
     ScriptPromise requestDevice(ScriptState*, const USBDeviceRequestOptions&);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(connect);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(disconnect);
+
+    // EventTarget overrides.
+    ExecutionContext* executionContext() const override;
+    const AtomicString& interfaceName() const override;
 
     DECLARE_VIRTUAL_TRACE();