Also, ensure the selected text is painted correctly when an ellipsis is present
in a mixed-flow context (e.g. ltr text in an rtl container).

BUG=642454, 642450, 642460
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2594983002
Cr-Commit-Position: refs/heads/master@{#441486}