Remove the SetConstant method.
Remove the SetConstant method.

It was used for backwards compatibility,
and we have not used it for a while now.

dsrbecky/gapid,google/gapid,google/agi,Qining/gapid,pmuetschard/gapid,google/agi,pmuetschard/gapid,google/gapid,google/agi,pmuetschard/gapid,dsrbecky/gapid,dsrbecky/gapid,Qining/gapid,baldwinn860/gapid,google/gapid,Qining/gapid,pmuetschard/gapid,baldwinn860/gapid,google/gapid,Qining/gapid,google/agi,google/gapid,Qining/gapid,dsrbecky/gapid,google/agi,google/agi,google/agi,baldwinn860/gapid,dsrbecky/gapid,pmuetschard/gapid,baldwinn860/gapid,google/gapid,Qining/gapid,baldwinn860/gapid,baldwinn860/gapid,baldwinn860/gapid,dsrbecky/gapid,pmuetschard/gapid,Qining/gapid,pmuetschard/gapid,google/gapid,Qining/gapid,pmuetschard/gapid,dsrbecky/gapid,dsrbecky/gapid,google/agi,baldwinn860/gapid,google/gapid