COMPMID-1808: Add Detection Output Layer to the GraphAPI
COMPMID-1710: Integrate Detection ouput in MobilenetSSD graph example

Change-Id: I384d1eb492ef14ece58f2023ad7bbc16f834450b
Reviewed-on: https://review.mlplatform.org/356
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Pablo Marquez <pablo.tello@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/arm_compute/graph/nodes/NodesFwd.h b/arm_compute/graph/nodes/NodesFwd.h
index f956b54..542c129 100644
--- a/arm_compute/graph/nodes/NodesFwd.h
+++ b/arm_compute/graph/nodes/NodesFwd.h
@@ -39,6 +39,7 @@
 class ConvolutionLayerNode;
 class DeconvolutionLayerNode;
 class DepthwiseConvolutionLayerNode;
+class DetectionOutputLayerNode;
 class DummyNode;
 class EltwiseLayerNode;
 class FlattenLayerNode;