Add chooser permission UI code for Mac

chrome/browser/usb/usb_chooser_bubble_delegate.h

Index: chrome/browser/usb/usb_chooser_bubble_delegate.h
diff --git a/chrome/browser/usb/usb_chooser_bubble_delegate.h b/chrome/browser/usb/usb_chooser_bubble_delegate.h
index b02b314c26a3c892ca1242eb38b48e3e68aac866..9d06131ff2a7ecf4339d402e4c959ca6698805ef 100644
--- a/chrome/browser/usb/usb_chooser_bubble_delegate.h
+++ b/chrome/browser/usb/usb_chooser_bubble_delegate.h
@@ -36,9 +36,6 @@ class UsbChooserBubbleDelegate : public ChooserBubbleDelegate,
       const webusb::WebUsbPermissionBubble::GetPermissionCallback& callback);
   ~UsbChooserBubbleDelegate() override;
 
-  // BubbleDelegate:
-  scoped_ptr<BubbleUi> BuildBubbleUi() override;
-
   // ChooserBubbleDelegate:
   const std::vector<base::string16>& GetOptions() const override;
   void Select(int index) override;
@@ -53,7 +50,6 @@ class UsbChooserBubbleDelegate : public ChooserBubbleDelegate,
       const std::vector<scoped_refptr<device::UsbDevice>>& devices);
 
  private:
-  Browser* browser_;
   content::RenderFrameHost* const render_frame_host_;
   webusb::WebUsbPermissionBubble::GetPermissionCallback callback_;
   ScopedObserver<device::UsbService, device::UsbService::Observer>