IVGCVSW-1963: Add implementation classes for Cl, Neon and Ref backends

Change-Id: Ibb2efaf8b001a64a3f35eab2220990dc39889780
diff --git a/src/backends/cl/ClBackend.hpp b/src/backends/cl/ClBackend.hpp
new file mode 100644
index 0000000..7e67f5e
--- /dev/null
+++ b/src/backends/cl/ClBackend.hpp
@@ -0,0 +1,33 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#pragma once
+
+#include "backends/IBackendInternal.hpp"
+
+#include "ClLayerSupport.hpp"
+
+namespace armnn
+{
+
+class ClBackend : public IBackendInternal
+{
+public:
+    ClBackend()  = default;
+    ~ClBackend() = default;
+
+    const std::string& GetId() const override;
+
+    const ILayerSupport& GetLayerSupport() const override;
+
+    std::unique_ptr<IWorkloadFactory> CreateWorkloadFactory() const override;
+
+private:
+    static const std::string s_Id;
+
+    // TODO initialize
+    ClLayerSupport m_LayerSupport;
+};
+
+} // namespace armnn
\ No newline at end of file