bluetooth: Save characteristic value when notification arrives

device/bluetooth/test/test_bluetooth_adapter_observer.cc

Index: device/bluetooth/test/test_bluetooth_adapter_observer.cc
diff --git a/device/bluetooth/test/test_bluetooth_adapter_observer.cc b/device/bluetooth/test/test_bluetooth_adapter_observer.cc
index 5cafda3fc5aa780ba8549a9fdc866f65b314480e..1ab083060d2bc1f54493d8542a476a13c38d5af4 100644
--- a/device/bluetooth/test/test_bluetooth_adapter_observer.cc
+++ b/device/bluetooth/test/test_bluetooth_adapter_observer.cc
@@ -60,6 +60,7 @@ void TestBluetoothAdapterObserver::Reset() {
   last_gatt_characteristic_id_.clear();
   last_gatt_characteristic_uuid_ = BluetoothUUID();
   last_changed_characteristic_value_.clear();
+  previous_characteristic_value_changed_values_.clear();
   last_gatt_descriptor_id_.clear();
   last_gatt_descriptor_uuid_ = BluetoothUUID();
   last_changed_descriptor_value_.clear();
@@ -302,6 +303,7 @@ void TestBluetoothAdapterObserver::GattCharacteristicValueChanged(
   last_gatt_characteristic_id_ = characteristic->GetIdentifier();
   last_gatt_characteristic_uuid_ = characteristic->GetUUID();
   last_changed_characteristic_value_ = value;
+  previous_characteristic_value_changed_values_.push_back(value);
 
   ASSERT_TRUE(characteristic->GetService());
   EXPECT_EQ(characteristic->GetService()->GetCharacteristic(