Add chrome side webusb permission UI code

chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.h

Index: chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.h
diff --git a/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.h b/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.h
new file mode 100644
index 0000000000000000000000000000000000000000..cfe31f9b49905bca317320dc0d2d6873d2368ab6
--- /dev/null
+++ b/chrome/browser/ui/cocoa/website_settings/chooser_bubble_ui_cocoa.h
@@ -0,0 +1,24 @@
+// 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_UI_COCOA_WEBSITE_SETTINGS_CHOOSER_BUBBLE_UI_COCOA_H_
+#define CHROME_BROWSER_UI_COCOA_WEBSITE_SETTINGS_CHOOSER_BUBBLE_UI_COCOA_H_
+
+#include "components/bubble/bubble_ui.h"
+
+// placeholder for Mac implementation of BubbleUi for chooser bubble
+class ChooserBubbleUiCocoa : public BubbleUi {
+ public:
+  ChooserBubbleUiCocoa();
+  ~ChooserBubbleUiCocoa() override;
+
+  // BubbleUi:
+  void Show(BubbleReference bubble_reference) override;
+  void Close() override;
+  void UpdateAnchorPosition() override;
+
+  void Update();
+};
+
+#endif  // CHROME_BROWSER_UI_COCOA_WEBSITE_SETTINGS_CHOOSER_BUBBLE_UI_COCOA_H_