Deprecate GetCodeRange(void** start, size_t* length_in_bytes) in favor
of a new signature MemoryRange GetCodeRange() which is consistent with
that of GetEmbeddedCodeRange.

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Ic5e244981422a2c75485c851ca768e54914cc539
Reviewed-on: https://chromium-review.googlesource.com/1245741Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56241}