Pass arguments to SkRecords structs by const&.

Pass arguments to SkRecords structs by const&.

This has the effect of using delay_copy() on every argument,
obviating the need for delay_copy() and, crucially, having
to remember to call delay_copy().

All these constructors are fully inlined, so we'll never pay
a penalty for passing small things by reference... the compiler
can see that and just pass by value.

BUG=skia:

Review URL: https://codereview.chromium.org/1215523004