Add webusb notification UI code

chrome/browser/webusb_detector_factory.cc

+// 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 "chrome/browser/webusb_detector_factory.h"
+
+#include "chrome/browser/profiles/profile.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "components/webusb/webusb_detector.h"
+
+namespace {
+
+static base::LazyInstance<WebUsbDetectorFactory> g_factory =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+// static
+WebUsbDetectorFactory* WebUsbDetectorFactory::GetInstance() {
+  return g_factory.Pointer();
+}
+
+webusb::WebUsbDetector* WebUsbDetectorFactory::Get(
+    content::BrowserContext* context) {
+  return static_cast<webusb::WebUsbDetector*>(
+      GetServiceForBrowserContext(context, false));
+}
+
+WebUsbDetectorFactory::WebUsbDetectorFactory()
+    : BrowserContextKeyedServiceFactory(
+          "WebUsbDetectorFactory",
+          BrowserContextDependencyManager::GetInstance()) {}
+
+WebUsbDetectorFactory::~WebUsbDetectorFactory() {}
+
+KeyedService* WebUsbDetectorFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  return new webusb::WebUsbDetector(Profile::FromBrowserContext(context));
+}
+
+bool WebUsbDetectorFactory::ServiceIsCreatedWithBrowserContext() const {
+  return true;
+}
+
+bool WebUsbDetectorFactory::ServiceIsNULLWhileTesting() const {
+  return true;
+}