Add webusb notification UI code

components/webusb/webusb_browser_client.h

Index: components/webusb/webusb_browser_client.h
diff --git a/components/webusb/webusb_browser_client.h b/components/webusb/webusb_browser_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..327aed2b2db52c0146f9df458a991a9e6a40394a
--- /dev/null
+++ b/components/webusb/webusb_browser_client.h
@@ -0,0 +1,39 @@
+// 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 COMPONENTS_WEBUSB_WEBUSB_BROWSER_CLIENT_H_
+#define COMPONENTS_WEBUSB_WEBUSB_BROWSER_CLIENT_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/strings/string16.h"
+
+class GURL;
+
+namespace webusb {
+
+// Interface to allow the webusb module to make browser-process-specific
+// calls. Should be Set() once in the browser process.
+
+class WebUsbBrowserClient {
+ public:
+  virtual ~WebUsbBrowserClient() {}
+
+  virtual void OnDeviceAdded(const base::string16& product_name,
+                             const GURL& landing_page,
+                             const std::string& notification_id) = 0;
+
+  virtual void OnDeviceRemoved(const std::string& notification_id) = 0;
+
+  // Returns the single instance of |this|.
+  static WebUsbBrowserClient* Get();

[stevenjb, 2015/08/28 16:55:06]

This doesn't appear to be used outside of WebUsbDetector. We should just pass
the WebUsbBrowserClient instance to the WebUsbDetector constructor.

[juncai, 2015/08/28 20:23:56]

Done.

+
+  // Initialize the single instance.
+  static void Set(WebUsbBrowserClient* client);
+};
+
+}  // namespace webusb
+
+#endif  // COMPONENTS_WEBUSB_WEBUSB_BROWSER_CLIENT_H_