Make new WebUSB implementation more resilient to garbage collection.

third_party/WebKit/Source/modules/webusb/USB.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef USB_h
 #define USB_h
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/ContextLifecycleObserver.h"
@@ skipping 34 matching lines @@
 
     // ContextLifecycleObserver overrides.
     void contextDestroyed() override;
 
     device::usb::wtf::DeviceManager* deviceManager() const { return m_deviceManager.get(); }
 
     void onGetDevices(ScriptPromiseResolver*, mojo::WTFArray<device::usb::wtf::DeviceInfoPtr>);
     void onGetPermission(ScriptPromiseResolver*, device::usb::wtf::DeviceInfoPtr);
     void onDeviceChanges(device::usb::wtf::DeviceChangeNotificationPtr);
 
+    void onDeviceManagerConnectionError();
+    void onChooserServiceConnectionError();
+
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit USB(LocalFrame& frame);
 
     device::usb::wtf::DeviceManagerPtr m_deviceManager;
     HeapHashSet<Member<ScriptPromiseResolver>> m_deviceManagerRequests;
     device::usb::wtf::ChooserServicePtr m_chooserService;
     HeapHashSet<Member<ScriptPromiseResolver>> m_chooserServiceRequests;
 };
 
 } // namespace blink
 
 #endif // USB_h