Lacros: Remove deprecated gn/macro variable names.

The patch removes is_lacros, is_ash, IS_LACROS and
IS_ASH which were aliases for is_chromeos_lacros,
is_chromeos_ash, IS_CHROMEOS_ASH and
IS_CHROMEOS_LACROS.

The names were changed to make it clearer that the
variables are related to CrOS.

Bug: 1052397
Change-Id: Id5b9b1b2ca3d34a9773ae73e4cc9408b9633e0ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2627529Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Yuta Hijikata <ythjkt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843305}

build/BUILD.gn

@@ -40,9 +40,6 @@ buildflag_header("chromeos_buildflags") {
   flags = [
     "IS_CHROMEOS_DEVICE=$is_chromeos_device",
 
-    # TODO(crbug.com/1052397): Remove IS_LACROS|ASH once all of them are replaced by IS_CHROMEOS_*.
-    "IS_LACROS=$is_chromeos_lacros",
-    "IS_ASH=$is_chromeos_ash",
     "IS_CHROMEOS_LACROS=$is_chromeos_lacros",
     "IS_CHROMEOS_ASH=$is_chromeos_ash",
   ]

build/config/chromeos/ui_mode.gni

@@ -34,9 +34,3 @@ is_chromeos_ash = is_chromeos && !chromeos_is_browser_only
 # TODO(crbug.com/1052397): Remove is_linux once lacros-chrome switches
 # to target_os=chromeos
 is_chromeos_lacros = (is_chromeos || is_linux) && chromeos_is_browser_only
-
-# TODO(crbug.com/1052397):
-# Remove is_ash|lacros once all are replaced by is_chromeos_*.
-# is_ash|lacros is deprecated. Use is_chromeos_ash|lacros instead.
-is_ash = is_chromeos_ash
-is_lacros = is_chromeos_lacros