This patch switches to a create-or-update pattern for paint property
updates of the local border box. This is a 6% improvement on
large-table-collapsed-border-change-with-text [1].

[1] tools/perf/run_benchmark blink_perf.paint --browser=content-shell-release --pageset-repeat=5 --extra-browser-args=--enable-slimming-paint-v2

BUG=645667
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2538273002
Cr-Commit-Position: refs/heads/master@{#435546}