IVGCVSW-4210 Create a public API for the common backend files

 * Create a public API for the common backend files
 * Move OutputHandler to armnn internal
 * Remove unused headers

Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I3e86d908b021e3561befa9d45158d87d2cbb18c0
diff --git a/src/backends/backendsCommon/CpuTensorHandle.hpp b/src/backends/backendsCommon/CpuTensorHandle.hpp
index 5fefc12..e6e59fc 100644
--- a/src/backends/backendsCommon/CpuTensorHandle.hpp
+++ b/src/backends/backendsCommon/CpuTensorHandle.hpp
@@ -2,17 +2,20 @@
 // Copyright © 2017 Arm Ltd. All rights reserved.
 // SPDX-License-Identifier: MIT
 //
+
 #pragma once
 
-#include "CpuTensorHandleFwd.hpp"
-#include "CompatibleTypes.hpp"
+#include <armnn/backends/CpuTensorHandleFwd.hpp>
+#include <armnn/backends/ITensorHandle.hpp>
 
 #include <armnn/TypesUtils.hpp>
 
-#include <backendsCommon/OutputHandler.hpp>
+#include <CompatibleTypes.hpp>
 
 #include <algorithm>
 
+#include <boost/assert.hpp>
+
 namespace armnn
 {