Add webusb notification UI code

chrome/browser/webusb_detector_factory.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 CHROME_BROWSER_WEBUSB_DETECTOR_FACTORY_H_
+#define CHROME_BROWSER_WEBUSB_DETECTOR_FACTORY_H_
+
+#include "base/lazy_instance.h"
+#include "base/macros.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace webusb {
+class WebUsbDetector;
+}
+
+class WebUsbDetectorFactory : public BrowserContextKeyedServiceFactory {
+ public:
+  static WebUsbDetectorFactory* GetInstance();
+
+  webusb::WebUsbDetector* Get(content::BrowserContext* context);
+
+ private:
+  friend struct base::DefaultLazyInstanceTraits<WebUsbDetectorFactory>;
+  WebUsbDetectorFactory();
+  ~WebUsbDetectorFactory() override;
+
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* browser_context) const override;
+  bool ServiceIsCreatedWithBrowserContext() const override;
+  bool ServiceIsNULLWhileTesting() const override;
+
+  DISALLOW_COPY_AND_ASSIGN(WebUsbDetectorFactory);
+};
+
+#endif  // CHROME_BROWSER_WEBUSB_DETECTOR_FACTORY_H_