The benefits of having a CPDFSDK_FormActionHandler instance in
CPDFSDK_ActionHandler are unclear. It does not add encapsulation, nor
simplicity to the logic.
CL is a driven-by clean up that merges CPDFSDK_FormActionHandler into
It takes the opportunity to delete CPDFSDK_ActionHandler (now) empty
constructor and destructor, in favor of compiler-generated ones.
No behavior change is expected, so no new tests are being added.