bluetooth: Require frame to be connected for stopNotifications to succeed.

third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp

Index: third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
diff --git a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
index 6ca66b2e66188fa85b0b1c404940edf86f35e5c9..df461634afbf54149e8873b58ca8a530ff6c5fc5 100644
--- a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
+++ b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
@@ -355,6 +355,12 @@ ScriptPromise BluetoothRemoteGATTCharacteristic::stopNotifications(
                                         "yet. See https://goo.gl/J6ASzs"));
 #endif  // OS(MACOSX)
 
+  if (!gatt()->connected()) {
+    return ScriptPromise::rejectWithDOMException(
+        scriptState,
+        DOMException::create(NetworkError, kGATTServerNotConnected));
+  }
+
   WebBluetooth* webbluetooth =
       BluetoothSupplement::fromScriptState(scriptState);
   ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);