see crbug.com/841460 , we recently hit some build issues when using
Goma + jumbo builds because of a conflict on the definition of CONST,
v8 defines it in globals.h and including windows.h also defines it. It
should be possible to fix this by adding a bunch of #undef CONST but it
seems a little bit hacky and might not always work (this could only fix
the problem temporary if the jumbo merge limit changes and cause some
include files to get included in a different order).

Renaming the v8 definition of CONST to kConst, this follows the
style guide guidelines: "there is no reason to change old code to use
constant-style names, unless the old names are actually causing a
compile-time problem"
(https://google.github.io/styleguide/cppguide.html#Enumerator_Names)

I also had to turn the PropertyConstness enum into an enum class to
avoid some conflicts (both PropertyConstness and VariableMode define
kConst).


Bug: chromium:841460
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I2b70b9095374e88a5ae364cc557b39f20a3ab60f
Reviewed-on: https://chromium-review.googlesource.com/1064197Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53413}