Replace DeviceManager::GetDeviceChanges with a client interface.

third_party/WebKit/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 "modules/webusb/USB.h"
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
@@ skipping 34 matching lines @@
     mojoFilter->has_protocol_code = filter.hasProtocolCode();
     if (mojoFilter->has_protocol_code)
         mojoFilter->protocol_code = filter.protocolCode();
     return mojoFilter;
 }
 
 } // namespace
 
 USB::USB(LocalFrame& frame)
     : ContextLifecycleObserver(frame.document())
+    , m_clientBinding(this)
 {
+    ThreadState::current()->registerPreFinalizer(this);
     frame.serviceRegistry()->connectToRemoteService(mojo::GetProxy(&m_deviceManager));
     m_deviceManager.set_connection_error_handler(createBaseCallback(bind(&USB::onDeviceManagerConnectionError, WeakPersistentThisPointer<USB>(this))));
-    // Set up two sequential calls to GetDeviceChanges to avoid latency.
-    m_deviceManager->GetDeviceChanges(createBaseCallback(bind<usb::DeviceChangeNotificationPtr>(&USB::onDeviceChanges, WeakPersistentThisPointer<USB>(this))));
-    m_deviceManager->GetDeviceChanges(createBaseCallback(bind<usb::DeviceChangeNotificationPtr>(&USB::onDeviceChanges, WeakPersistentThisPointer<USB>(this))));
+    m_deviceManager->SetClient(m_clientBinding.CreateInterfacePtrAndBind());
 }
 
 USB::~USB()
 {
     // |m_deviceManager| and |m_chooserService| may still be valid but there
     // should be no more outstanding requests to them because each holds a
     // persistent handle to this object.
     DCHECK(m_deviceManagerRequests.isEmpty());
     DCHECK(m_chooserServiceRequests.isEmpty());
 }
 
+void USB::dispose()
+{
+    // The pipe to this object must be closed when is marked unreachable to
+    // prevent messages from being dispatched before lazy sweeping.
+    m_clientBinding.Close();
+}
+
 ScriptPromise USB::getDevices(ScriptState* scriptState)
 {
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
     if (!m_deviceManager) {
         resolver->reject(DOMException::create(NotSupportedError));
     } else {
         String errorMessage;
         if (!scriptState->getExecutionContext()->isSecureContext(errorMessage)) {
             resolver->reject(DOMException::create(SecurityError, errorMessage));
@@ skipping 87 matching lines @@
 
     if (deviceInfo) {
         usb::DevicePtr device;
         m_deviceManager->GetDevice(deviceInfo->guid, mojo::GetProxy(&device));
         resolver->resolve(USBDevice::create(std::move(deviceInfo), std::move(device), resolver->getExecutionContext()));
     } else {
         resolver->reject(DOMException::create(NotFoundError, "No device selected."));
     }
 }
 
-void USB::onDeviceChanges(usb::DeviceChangeNotificationPtr notification)
+void USB::OnDeviceAdded(usb::DeviceInfoPtr deviceInfo)
 {
-    m_deviceManager->GetDeviceChanges(createBaseCallback(bind<usb::DeviceChangeNotificationPtr>(&USB::onDeviceChanges, WeakPersistentThisPointer<USB>(this))));
-    for (auto& deviceInfo : notification->devices_added.PassStorage()) {
-        usb::DevicePtr device;
-        m_deviceManager->GetDevice(deviceInfo->guid, mojo::GetProxy(&device));
-        dispatchEvent(USBConnectionEvent::create(EventTypeNames::connect, USBDevice::create(std::move(deviceInfo), std::move(device), getExecutionContext())));
-    }
-    for (auto& deviceInfo : notification->devices_removed.PassStorage())
-        dispatchEvent(USBConnectionEvent::create(EventTypeNames::disconnect, USBDevice::create(std::move(deviceInfo), nullptr, getExecutionContext())));
+    if (!m_deviceManager)
+        return;
+
+    usb::DevicePtr device;
+    m_deviceManager->GetDevice(deviceInfo->guid, mojo::GetProxy(&device));
+    dispatchEvent(USBConnectionEvent::create(EventTypeNames::connect, USBDevice::create(std::move(deviceInfo), std::move(device), getExecutionContext())));
+}
+
+void USB::OnDeviceRemoved(usb::DeviceInfoPtr deviceInfo)
+{
+    dispatchEvent(USBConnectionEvent::create(EventTypeNames::disconnect, USBDevice::create(std::move(deviceInfo), nullptr, getExecutionContext())));
 }
 
 void USB::onDeviceManagerConnectionError()
 {
     m_deviceManager.reset();
     for (ScriptPromiseResolver* resolver : m_deviceManagerRequests)
         resolver->reject(DOMException::create(NotFoundError, kNoServiceError));
     m_deviceManagerRequests.clear();
 }
 
 void USB::onChooserServiceConnectionError()
 {
     m_chooserService.reset();
     for (ScriptPromiseResolver* resolver : m_chooserServiceRequests)
         resolver->reject(DOMException::create(NotFoundError, kNoServiceError));
     m_chooserServiceRequests.clear();
 }
 
 DEFINE_TRACE(USB)
 {
     EventTargetWithInlineData::trace(visitor);
     ContextLifecycleObserver::trace(visitor);
     visitor->trace(m_deviceManagerRequests);
     visitor->trace(m_chooserServiceRequests);
 }
 
 } // namespace blink