Implement USB connection events through the WebUSB client interface.

Source/modules/webusb/USB.cpp

 // 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.
 
 #include "config.h"
 #include "modules/webusb/USB.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "modules/EventTargetModules.h"
+#include "modules/webusb/USBConnectionEvent.h"
 #include "modules/webusb/USBDevice.h"
 #include "modules/webusb/USBDeviceFilter.h"
 #include "modules/webusb/USBDeviceRequestOptions.h"
 #include "modules/webusb/USBError.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebVector.h"
 #include "public/platform/modules/webusb/WebUSBClient.h"
 #include "public/platform/modules/webusb/WebUSBDeviceFilter.h"
 #include "public/platform/modules/webusb/WebUSBDeviceRequestOptions.h"
 #include "public/platform/modules/webusb/WebUSBError.h"
@@ skipping 46 matching lines @@
 
 private:
     DeviceArray() = delete;
 };
 
 } // namespace
 
 USB::USB(LocalFrame& frame)
     : m_controller(USBController::from(frame))
 {
+    WebUSBClient* client = m_controller->client();
+    if (client)
+        client->setObserver(this);
+}
+
+USB::~USB()
+{
+    WebUSBClient* client = m_controller->client();
+    if (client)
+        client->setObserver(nullptr);
 }
 
 ScriptPromise USB::getDevices(ScriptState* scriptState)
 {
     WebUSBClient* client = m_controller->client();
     if (!client)
         return ScriptPromise::rejectWithDOMException(scriptState, DOMException::create(NotSupportedError));
 
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
@@ skipping 22 matching lines @@
 {
     LocalFrame* frame = m_controller->frame();
     return frame ? frame->document() : nullptr;
 }
 
 const AtomicString& USB::interfaceName() const
 {
     return EventTargetNames::USB;
 }
 
+void USB::onDeviceConnected(WebPassOwnPtr<WebUSBDevice> device)
+{
+    dispatchEvent(USBConnectionEvent::create(EventTypeNames::connect, USBDevice::create(device.release())));
+}
+
+void USB::onDeviceDisconnected(WebPassOwnPtr<WebUSBDevice> device)
+{
+    dispatchEvent(USBConnectionEvent::create(EventTypeNames::disconnect, USBDevice::create(device.release())));
+}
+
 DEFINE_TRACE(USB)
 {
     visitor->trace(m_controller);
     RefCountedGarbageCollectedEventTargetWithInlineData<USB>::trace(visitor);
 }
 
 } // namespace blink