IVGCVSW-5012 Enable zero copy for Neon

 * Allow memory import if padding is not required in Neon
 * AddMockImportBackend for fallback tests
 * Refactor GraphUtils
 * Memory import unit tests
 * Fallback unit tests

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: Ic2e141e12774bf6d915e77745b6f6d2d83d9b82d
diff --git a/src/backends/backendsCommon/test/mockBackend/MockImportBackend.hpp b/src/backends/backendsCommon/test/mockBackend/MockImportBackend.hpp
new file mode 100644
index 0000000..ecc661f
--- /dev/null
+++ b/src/backends/backendsCommon/test/mockBackend/MockImportBackend.hpp
@@ -0,0 +1,53 @@
+//
+// Copyright © 2020 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#pragma once
+
+#include <armnn/backends/IBackendInternal.hpp>
+
+namespace armnn
+{
+
+constexpr const char* MockImportBackendId() { return "MockRef"; }
+
+class MockImportBackendInitialiser
+{
+public:
+    MockImportBackendInitialiser();
+    ~MockImportBackendInitialiser();
+};
+
+class MockImportBackend : public IBackendInternal
+{
+public:
+    MockImportBackend()  = default;
+    ~MockImportBackend() = default;
+
+    static const BackendId& GetIdStatic();
+    const BackendId& GetId() const override { return GetIdStatic(); }
+
+    IBackendInternal::IMemoryManagerUniquePtr CreateMemoryManager() const override;
+
+    IBackendInternal::IWorkloadFactoryPtr CreateWorkloadFactory(
+        const IBackendInternal::IMemoryManagerSharedPtr& memoryManager = nullptr) const override;
+
+    IBackendInternal::IWorkloadFactoryPtr CreateWorkloadFactory(
+        class TensorHandleFactoryRegistry& tensorHandleFactoryRegistry) const override;
+
+    IBackendInternal::IBackendContextPtr CreateBackendContext(const IRuntime::CreationOptions&) const override;
+
+    IBackendInternal::IBackendProfilingContextPtr CreateBackendProfilingContext(
+        const IRuntime::CreationOptions& creationOptions, IBackendProfilingPtr& backendProfiling) override;
+
+    IBackendInternal::Optimizations GetOptimizations() const override;
+    IBackendInternal::ILayerSupportSharedPtr GetLayerSupport() const override;
+
+    OptimizationViews OptimizeSubgraphView(const SubgraphView& subgraph) const override;
+
+    std::vector<ITensorHandleFactory::FactoryId> GetHandleFactoryPreferences() const override;
+
+    void RegisterTensorHandleFactories(class TensorHandleFactoryRegistry& registry) override;
+};
+
+} // namespace armnn