arc: bluetooth: Implement sending indications in GATT server

 - Ensure that CCCD is added such that we can report the value change in
   CCCD to Android in OnNotificationStart/Stop()
 - Implement SendIndication() such that Android can call it

Bug: b:78593133
Test: Pass Android CtsVerifier test on server sending indication/notification
Change-Id: I8b1a4be6596555003d6d447b4518f37632a45370
Reviewed-on: https://chromium-review.googlesource.com/1119079
Commit-Queue: Qiyu Hu <qiyuh@google.com>
Reviewed-by: Luis Hector Chavez <lhchavez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572291}

chrome/browser/chromeos/arc/bluetooth/arc_bluetooth_bridge.cc

@@ -43,6 +43,7 @@
 #include "device/bluetooth/bluetooth_local_gatt_characteristic.h"
 #include "device/bluetooth/bluetooth_local_gatt_descriptor.h"
 #include "device/bluetooth/bluez/bluetooth_device_bluez.h"
+#include "device/bluetooth/bluez/bluetooth_local_gatt_characteristic_bluez.h"
 #include "device/bluetooth/bluez/bluetooth_remote_gatt_characteristic_bluez.h"
 #include "mojo/public/cpp/platform/platform_handle.h"
 #include "mojo/public/cpp/system/platform_handle.h"
@@ -381,6 +382,24 @@ void OnRemoveServiceRecordError(
   std::move(callback).Run(status);
 }
 
+const device::BluetoothLocalGattDescriptor* FindCCCD(
+    const device::BluetoothLocalGattCharacteristic* characteristic) {
+  for (const auto& descriptor :
+       static_cast<const bluez::BluetoothLocalGattCharacteristicBlueZ*>(
+           characteristic)
+           ->GetDescriptors()) {
+    if (descriptor->GetUUID() ==
+        BluetoothGattDescriptor::ClientCharacteristicConfigurationUuid()) {
+      return descriptor.get();
+    }
+  }
+  return nullptr;
+}
+
+std::vector<uint8_t> MakeCCCDValue(uint8_t value) {
+  return {value, 0};
+}
+
 }  // namespace
 
 namespace arc {
@@ -897,11 +916,30 @@ void ArcBluetoothBridge::OnDescriptorWriteRequest(
 void ArcBluetoothBridge::OnNotificationsStart(
     const BluetoothDevice* device,
     device::BluetoothGattCharacteristic::NotificationType notification_type,
-    const BluetoothLocalGattCharacteristic* characteristic) {}
+    const BluetoothLocalGattCharacteristic* characteristic) {
+  const BluetoothLocalGattDescriptor* cccd = FindCCCD(characteristic);
+  if (cccd == nullptr)
+    return;
+  OnDescriptorWriteRequest(
+      device, cccd,
+      MakeCCCDValue(notification_type ==
+                            device::BluetoothRemoteGattCharacteristic::
+                                NotificationType::kNotification
+                        ? ENABLE_NOTIFICATION_VALUE
+                        : ENABLE_INDICATION_VALUE),
+      0, base::DoNothing(), base::DoNothing());
+}
 
 void ArcBluetoothBridge::OnNotificationsStop(
     const BluetoothDevice* device,
-    const BluetoothLocalGattCharacteristic* characteristic) {}
+    const BluetoothLocalGattCharacteristic* characteristic) {
+  const BluetoothLocalGattDescriptor* cccd = FindCCCD(characteristic);
+  if (cccd == nullptr)
+    return;
+  OnDescriptorWriteRequest(device, cccd,
+                           MakeCCCDValue(DISABLE_NOTIFICATION_VALUE), 0,
+                           base::DoNothing(), base::DoNothing());
+}
 
 void ArcBluetoothBridge::EnableAdapter(EnableAdapterCallback callback) {
   DCHECK(bluetooth_adapter_);
@@ -1927,14 +1965,6 @@ void ArcBluetoothBridge::AddDescriptor(int32_t service_handle,
     std::move(callback).Run(kInvalidGattAttributeHandle);
     return;
   }
-  // Chrome automatically adds a CCC Descriptor to a characteristic when needed.
-  // We will generate a bogus handle for Android.
-  if (uuid ==
-      BluetoothGattDescriptor::ClientCharacteristicConfigurationUuid()) {
-    int32_t handle = GetNextGattServerAttributeHandle();
-    std::move(callback).Run(handle);
-    return;
-  }
 
   DCHECK(gatt_identifier_.find(service_handle) != gatt_identifier_.end());
   BluetoothLocalGattService* service =
@@ -2008,7 +2038,34 @@ void ArcBluetoothBridge::SendIndication(int32_t attribute_handle,
                                         mojom::BluetoothAddressPtr address,
                                         bool confirm,
                                         const std::vector<uint8_t>& value,
-                                        SendIndicationCallback callback) {}
+                                        SendIndicationCallback callback) {
+  BluetoothDevice* device =
+      bluetooth_adapter_->GetDevice(address->To<std::string>());
+  auto identifier = gatt_identifier_.find(attribute_handle);
+  if (device == nullptr || identifier == gatt_identifier_.end()) {
+    std::move(callback).Run(mojom::BluetoothGattStatus::GATT_FAILURE);
+    return;
+  }
+
+  for (const auto& service_handle : last_characteristic_) {
+    auto it = gatt_identifier_.find(service_handle.first);
+    if (it == gatt_identifier_.end())
+      continue;
+    BluetoothLocalGattService* service =
+        bluetooth_adapter_->GetGattService(it->second);
+    if (service == nullptr)
+      continue;
+    BluetoothLocalGattCharacteristic* characteristic =
+        service->GetCharacteristic(identifier->second);
+    if (characteristic == nullptr)
+      continue;
+    characteristic->NotifyValueChanged(device, value, confirm);
+    std::move(callback).Run(mojom::BluetoothGattStatus::GATT_SUCCESS);
+    return;
+  }
+
+  std::move(callback).Run(mojom::BluetoothGattStatus::GATT_FAILURE);
+}
 
 void ArcBluetoothBridge::GetSdpRecords(mojom::BluetoothAddressPtr remote_addr,
                                        const BluetoothUUID& target_uuid) {