`viewops_data_alloc` allocates and stores some pointers in
`ViewOpsData` while `viewops_data_create` reuses already stored
pointers and also stores others in `ViewOpsData`.
The similar names and usages can confuse and in this case it also
creates a dependency on the order in which these functions are called.
Merging these functions simplifies usage and deduplicates code.
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