Implement BluetoothRemoteGattCharacteristicWin::StartNotifySession and related unit tests

device/bluetooth/bluetooth_low_energy_win_fake.cc

Index: device/bluetooth/bluetooth_low_energy_win_fake.cc
diff --git a/device/bluetooth/bluetooth_low_energy_win_fake.cc b/device/bluetooth/bluetooth_low_energy_win_fake.cc
index 548286d3a2335deda27fa714774a568b128feae5..629c1a3fe93150d2bf2c6b0481509d92e3626152 100644
--- a/device/bluetooth/bluetooth_low_energy_win_fake.cc
+++ b/device/bluetooth/bluetooth_low_energy_win_fake.cc
@@ -27,6 +27,9 @@ GattCharacteristic::~GattCharacteristic() {}
 GattDescriptor::GattDescriptor() {}
 GattDescriptor::~GattDescriptor() {}
 
+GattCharacteristicObserver::GattCharacteristicObserver() {}
+GattCharacteristicObserver::~GattCharacteristicObserver() {}
+
 BluetoothLowEnergyWrapperFake::BluetoothLowEnergyWrapperFake()
     : observer_(nullptr) {}
 BluetoothLowEnergyWrapperFake::~BluetoothLowEnergyWrapperFake() {}
@@ -186,8 +189,12 @@ HRESULT BluetoothLowEnergyWrapperFake::ReadCharacteristicValue(
     scoped_ptr<BTH_LE_GATT_CHARACTERISTIC_VALUE>* out_value) {
   GattCharacteristic* target_characteristic =
       GetSimulatedGattCharacteristic(service_path, characteristic);
-  if (target_characteristic == nullptr)
-    return HRESULT_FROM_WIN32(ERROR_NOT_FOUND);
+  if (target_characteristic == nullptr) {
+    target_characteristic = remembered_characteristic_.get();
+    DCHECK(target_characteristic);
+    DCHECK(target_characteristic->characteristic_info->AttributeHandle ==
+           characteristic->AttributeHandle);
+  }
 
   // Return error simulated by SimulateGattCharacteristicReadError.
   if (target_characteristic->read_errors.size()) {
@@ -204,6 +211,8 @@ HRESULT BluetoothLowEnergyWrapperFake::ReadCharacteristicValue(
   for (ULONG i = 0; i < ret_value->DataSize; i++)
     ret_value->Data[i] = target_characteristic->value->Data[i];
   out_value->reset(ret_value);
+  if (observer_)
+    observer_->OnReadGattCharacteristicValue();
   return S_OK;
 }
 
@@ -213,8 +222,12 @@ HRESULT BluetoothLowEnergyWrapperFake::WriteCharacteristicValue(
     PBTH_LE_GATT_CHARACTERISTIC_VALUE new_value) {
   GattCharacteristic* target_characteristic =
       GetSimulatedGattCharacteristic(service_path, characteristic);
-  if (target_characteristic == nullptr)
-    return ERROR_NOT_FOUND;
+  if (target_characteristic == nullptr) {
+    target_characteristic = remembered_characteristic_.get();
+    DCHECK(target_characteristic);
+    DCHECK(target_characteristic->characteristic_info->AttributeHandle ==
+           characteristic->AttributeHandle);
+  }
 
   // Return error simulated by SimulateGattCharacteristicWriteError.
   if (target_characteristic->write_errors.size()) {
@@ -232,7 +245,66 @@ HRESULT BluetoothLowEnergyWrapperFake::WriteCharacteristicValue(
   win_value->DataSize = new_value->DataSize;
   target_characteristic->value.reset(win_value);
   if (observer_)
-    observer_->onWriteGattCharacteristicValue(win_value);
+    observer_->OnWriteGattCharacteristicValue(win_value);
+  return S_OK;
+}
+
+HRESULT BluetoothLowEnergyWrapperFake::RegisterGattEvents(
+    base::FilePath& service_path,
+    BTH_LE_GATT_EVENT_TYPE type,
+    PVOID event_parameter,
+    PFNBLUETOOTH_GATT_EVENT_CALLBACK callback,
+    PVOID context,
+    BLUETOOTH_GATT_EVENT_HANDLE* out_handle) {
+  // Right now, only CharacteristicValueChangedEvent is supported.
+  CHECK(CharacteristicValueChangedEvent == type);
+
+  scoped_ptr<GattCharacteristicObserver> observer(
+      new GattCharacteristicObserver());
+  observer->callback = callback;
+  observer->context = context;
+  *out_handle = (BLUETOOTH_GATT_EVENT_HANDLE)observer.get();
+  gatt_characteristic_observers_[*out_handle] = std::move(observer);
+
+  PBLUETOOTH_GATT_VALUE_CHANGED_EVENT_REGISTRATION parameter =
+      (PBLUETOOTH_GATT_VALUE_CHANGED_EVENT_REGISTRATION)event_parameter;
+  for (USHORT i = 0; i < parameter->NumCharacteristics; i++) {
+    GattCharacteristic* target_characteristic = GetSimulatedGattCharacteristic(
+        service_path, &parameter->Characteristics[i]);
+    CHECK(target_characteristic);
+    target_characteristic->observers.push_back(*out_handle);
+  }
+
+  if (observer_)
+    observer_->OnStartCharacteristicNotification();
+
+  return S_OK;
+}
+
+HRESULT BluetoothLowEnergyWrapperFake::UnregisterGattEvent(
+    BLUETOOTH_GATT_EVENT_HANDLE event_handle) {
+  gatt_characteristic_observers_.erase(event_handle);
+  return S_OK;
+}
+
+HRESULT BluetoothLowEnergyWrapperFake::WriteDescriptorValue(
+    base::FilePath& service_path,
+    const PBTH_LE_GATT_DESCRIPTOR descriptor,
+    PBTH_LE_GATT_DESCRIPTOR_VALUE new_value) {
+  if (new_value->DescriptorType == ClientCharacteristicConfiguration) {
+    // Simulate the value the OS will write.
+    std::vector<UCHAR> write_value;
+    if (new_value->ClientCharacteristicConfiguration
+            .IsSubscribeToNotification) {
+      write_value.push_back(1);
+    } else if (new_value->ClientCharacteristicConfiguration
+                   .IsSubscribeToIndication) {
+      write_value.push_back(2);
+    }
+    write_value.push_back(0);
+    if (observer_)
+      observer_->OnWriteGattDescriptorValue(write_value);
+  }
   return S_OK;
 }
 
@@ -342,6 +414,11 @@ GattCharacteristic* BluetoothLowEnergyWrapperFake::SimulateGattCharacterisc(
   parent_service->included_characteristics[std::to_string(
       win_characteristic->characteristic_info->AttributeHandle)] =
       make_scoped_ptr(win_characteristic);
+  // Set default empty value.
+  PBTH_LE_GATT_CHARACTERISTIC_VALUE win_value =
+      (PBTH_LE_GATT_CHARACTERISTIC_VALUE)(new UCHAR[sizeof(ULONG)]);

[scheib, 2016/04/05 22:44:02]

sizeof(BTH_LE_GATT_CHARACTERISTIC_VALUE) 

[gogerald1, 2016/04/06 22:54:48]

Done.

+  win_value->DataSize = 0;
+  win_characteristic->value.reset(win_value);
   return win_characteristic;
 }
 
@@ -367,14 +444,42 @@ BluetoothLowEnergyWrapperFake::GetSimulatedGattCharacteristic(
 void BluetoothLowEnergyWrapperFake::SimulateGattCharacteristicValue(
     GattCharacteristic* characteristic,
     const std::vector<uint8_t>& value) {
-  CHECK(characteristic);
+  GattCharacteristic* target_characteristic = characteristic;
+  if (target_characteristic == nullptr)
+    target_characteristic = remembered_characteristic_.get();
+  CHECK(target_characteristic);
+
   PBTH_LE_GATT_CHARACTERISTIC_VALUE win_value =
       (PBTH_LE_GATT_CHARACTERISTIC_VALUE)(
           new UCHAR[value.size() + sizeof(ULONG)]);
   win_value->DataSize = (ULONG)value.size();
   for (std::size_t i = 0; i < value.size(); i++)
     win_value->Data[i] = value[i];
-  characteristic->value.reset(win_value);
+  target_characteristic->value.reset(win_value);
+}
+
+void BluetoothLowEnergyWrapperFake::
+    SimulateCharacteristicValueChangeNotification(
+        GattCharacteristic* characteristic) {
+  GattCharacteristic* target_characteristic = characteristic;
+  if (target_characteristic == nullptr)
+    target_characteristic = remembered_characteristic_.get();
+  CHECK(target_characteristic);
+  for (const auto& observer : target_characteristic->observers) {
+    GattCharacteristicObserverTable::const_iterator it =
+        gatt_characteristic_observers_.find(observer);
+    // Check if |observer| has been unregistered by UnregisterGattEvent.
+    if (it != gatt_characteristic_observers_.end()) {
+      BLUETOOTH_GATT_VALUE_CHANGED_EVENT event;
+      event.ChangedAttributeHandle =
+          target_characteristic->characteristic_info->AttributeHandle;
+      event.CharacteristicValueDataSize =
+          target_characteristic->value->DataSize + sizeof(ULONG);
+      event.CharacteristicValue = target_characteristic->value.get();
+      it->second->callback(CharacteristicValueChangedEvent, &event,
+                           it->second->context);
+    }
+  }
 }
 
 void BluetoothLowEnergyWrapperFake::SimulateGattCharacteristicReadError(
@@ -391,6 +496,16 @@ void BluetoothLowEnergyWrapperFake::SimulateGattCharacteristicWriteError(
   characteristic->write_errors.push_back(error);
 }
 
+void BluetoothLowEnergyWrapperFake::RememberCharacteristicForSubsequentAction(
+    GattService* parent_service,
+    std::string attribute_handle) {
+  CHECK(parent_service);
+  GattCharacteristicsMap::iterator it =
+      parent_service->included_characteristics.find(attribute_handle);
+  DCHECK(it != parent_service->included_characteristics.end());
+  remembered_characteristic_ = std::move(it->second);

[scheib, 2016/04/05 22:44:02]

Are you intending to move the characteristic out of the
parent_service->included_characteristics? 

If so, use remembered_characteristic_.swap(it->second), and call out in comments
what is happening. (it's not as obvious, because of the iterator reference)

remembered_characteristic_.swap(parent_service->included_characteristics[attribute_handle]);
would be even clearer.

But, if we can get away without doing so it would be best. The reason to do so
would be that the unittest code deleting the device must result in the service
being deleted. but if it is possible to only delete the chrome implementation
objects, and keep the fake objects alive, that would be better at reflecting the
intent of the tests: The OS have objects alive and valid while our objects are
destroyed. 

[gogerald1, 2016/04/06 22:54:48]

Done.

+}
+
 void BluetoothLowEnergyWrapperFake::SimulateGattDescriptor(
     std::string device_address,
     GattCharacteristic* characteristic,