Add DBus plumbing and tests for sending devices with ATT read/writes.

device/bluetooth/dbus/fake_bluetooth_gatt_descriptor_service_provider.cc

Index: device/bluetooth/dbus/fake_bluetooth_gatt_descriptor_service_provider.cc
diff --git a/device/bluetooth/dbus/fake_bluetooth_gatt_descriptor_service_provider.cc b/device/bluetooth/dbus/fake_bluetooth_gatt_descriptor_service_provider.cc
index 2e9261a0cdb4b97cb7619bc826d32729a1000d00..3c39ab3ef650789e2c121bee97e165aabb4659e4 100644
--- a/device/bluetooth/dbus/fake_bluetooth_gatt_descriptor_service_provider.cc
+++ b/device/bluetooth/dbus/fake_bluetooth_gatt_descriptor_service_provider.cc
@@ -96,6 +96,7 @@ void FakeBluetoothGattDescriptorServiceProvider::SendValueChanged(
 }
 
 void FakeBluetoothGattDescriptorServiceProvider::GetValue(
+    const dbus::ObjectPath& device_path,
     const device::BluetoothLocalGattService::Delegate::ValueCallback& callback,
     const device::BluetoothLocalGattService::Delegate::ErrorCallback&
         error_callback) {
@@ -128,10 +129,11 @@ void FakeBluetoothGattDescriptorServiceProvider::GetValue(
 
   // Pass on to the delegate.
   DCHECK(delegate_);
-  delegate_->GetValue(callback, error_callback);
+  delegate_->GetValue(device_path, callback, error_callback);
 }
 
 void FakeBluetoothGattDescriptorServiceProvider::SetValue(
+    const dbus::ObjectPath& device_path,
     const std::vector<uint8_t>& value,
     const base::Closure& callback,
     const device::BluetoothLocalGattService::Delegate::ErrorCallback&
@@ -166,7 +168,7 @@ void FakeBluetoothGattDescriptorServiceProvider::SetValue(
 
   // Pass on to the delegate.
   DCHECK(delegate_);
-  delegate_->SetValue(value, callback, error_callback);
+  delegate_->SetValue(device_path, value, callback, error_callback);
 }
 
 const dbus::ObjectPath&