Add throbber and status text to WebBluetooth chooser UI on non-Mac desktops

chrome/browser/usb/usb_chooser_controller.h

Index: chrome/browser/usb/usb_chooser_controller.h
diff --git a/chrome/browser/usb/usb_chooser_controller.h b/chrome/browser/usb/usb_chooser_controller.h
index a7e472fee1c9848dabdbb45d70205978ec3f0924..c713112e8f54fc1d6ddf4b6ada70c96b6957518c 100644
--- a/chrome/browser/usb/usb_chooser_controller.h
+++ b/chrome/browser/usb/usb_chooser_controller.h
@@ -40,9 +40,12 @@ class UsbChooserController : public ChooserController,
   ~UsbChooserController() override;
 
   // ChooserController:
+  base::string16 GetNoOptionsText() const override;
   base::string16 GetOkButtonLabel() const override;
   size_t NumOptions() const override;
   base::string16 GetOption(size_t index) const override;
+  void RefreshOptions() override;
+  base::string16 GetStatus() const override;
   void Select(size_t index) override;
   void Cancel() override;
   void Close() override;