dns: Reduce redundant comparisons in FindAddressListDeltaType()

In FindAddressListDeltaType(), always spend O(nxn) to compare two
AddressLists. If any match has occurred before, but the current does
not match, or vice versa, so these two AddressLists are definitely
DELTA_OVERLAP. The CL fixes it.

Change-Id: I44f0c3824eb8376949a59b433bf9154707a50d47
Reviewed-on: https://chromium-review.googlesource.com/c/1371684
Reviewed-by: Eric Orth <ericorth@chromium.org>
Commit-Queue: Eric Orth <ericorth@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616462}
1 file changed