Refactor Forced Import

 * Find and replace all workloads associated with imported IO
 * Only attempt tensorhandle replacement if supported by all workloads
 * Add new RefBaseWorkload to enable forced input for ref backend
 * Store imported tensorhandles in preImportedTensorhandles instead of outputHandles
 * Create pre-imported tensorhandles at network load-time
 * Front load import workload validation to load network time
 * Only call ReplaceTensorHandle when needed

Change-Id: I3816a71b7f57ae90388bb16462a75d4ef3544fa7
Signed-off-by: Finn Williams <finn.williams@arm.com>
diff --git a/src/backends/reference/workloads/RefSliceWorkload.hpp b/src/backends/reference/workloads/RefSliceWorkload.hpp
index 69dae5a..b9dca86 100644
--- a/src/backends/reference/workloads/RefSliceWorkload.hpp
+++ b/src/backends/reference/workloads/RefSliceWorkload.hpp
@@ -5,16 +5,16 @@
 
 #pragma once
 
-#include <armnn/backends/Workload.hpp>
+#include "RefBaseWorkload.hpp"
 #include <armnn/backends/WorkloadData.hpp>
 
 namespace armnn
 {
 
-class RefSliceWorkload : public BaseWorkload<SliceQueueDescriptor>
+class RefSliceWorkload : public RefBaseWorkload<SliceQueueDescriptor>
 {
 public:
-    using BaseWorkload<SliceQueueDescriptor>::BaseWorkload;
+    using RefBaseWorkload<SliceQueueDescriptor>::RefBaseWorkload;
 
     void Execute() const override;
     void ExecuteAsync(WorkingMemDescriptor& workingMemDescriptor)  override;