Merge topic 'allow_empty_field_construction'

c2ba8baf Allow vtkm::cont::Field to have a default constructor.

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Kenneth Moreland <kmorel@sandia.gov>
Merge-request: !297

vtkm/cont/Field.h

@@ -534,6 +534,20 @@ public:
     VTKM_ASSERT_CONT(this->Association == ASSOC_LOGICAL_DIM);
   }
 
+  VTKM_CONT_EXPORT
+  Field()
+    : Name(),
+      Order(),
+      Association(),
+      AssocCellSetName(),
+      AssocLogicalDim(),
+      Data(),
+      Bounds(),
+      ModifiedFlag(true)
+  {
+    //Generate an empty field
+  }
+
   VTKM_CONT_EXPORT
   const std::string &GetName() const
   {