bluetooth: Clean up WebBluetoothServiceImpl when adapter is removed

content/browser/bluetooth/bluetooth_dispatcher_host.cc

Index: content/browser/bluetooth/bluetooth_dispatcher_host.cc
diff --git a/content/browser/bluetooth/bluetooth_dispatcher_host.cc b/content/browser/bluetooth/bluetooth_dispatcher_host.cc
index 78d8c12391f6f614c079fccffdce789b86a95245..2c9a3eb4f04e2ef287131a7bb5c1b703a8290e1c 100644
--- a/content/browser/bluetooth/bluetooth_dispatcher_host.cc
+++ b/content/browser/bluetooth/bluetooth_dispatcher_host.cc
@@ -483,6 +483,12 @@ void BluetoothDispatcherHost::set_adapter(
     for (device::BluetoothAdapter::Observer* observer : adapter_observers_) {
       adapter_->AddObserver(observer);
     }
+  } else {
+    // Notify that the adapter has been removed and observers should clean up
+    // their state.
+    for (device::BluetoothAdapter::Observer* observer : adapter_observers_) {
+      observer->AdapterPresentChanged(nullptr, false);
+    }
   }
 }