Move SaturatedSet functions to platform/geometry/layout_unit.h. The ARM
asm versions in wtf/saturated_arithmetic_arm.h were moved there too and
some variables were inlined. Do the same with the corresponding tests.
Bug: 943947
Change-Id: I5485ad83f48016245dca1edae27d41ca9ced2772
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1534169
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Cr-Commit-Position: refs/heads/master@{#645508}