Delete obsolete XPointer range-to function.

BUG=623378

Review-Url: https://codereview.chromium.org/2127493002
Cr-Commit-Position: refs/heads/master@{#403859}
(cherry picked from commit b6ad54b72c7f8c422c288dd9c8756d2a15f30e53)
TBR=inferno@chromium.org

Review URL: https://codereview.chromium.org/2154173003 .

Cr-Commit-Position: refs/branch-heads/2743@{#669}
Cr-Branched-From: 2b3ae3b8090361f8af5a611712fc1a5ab2de53cb-refs/heads/master@{#394939}
3 files changed