Reland "compiler: remove `!is_android` from CrOS thinlto checks"

This is a reland of 5c44b2a9.
Originally reverted by I57aafeaa0e4f6bb60c22f8ea0b085282869fffd7.

Original change's description:
> compiler: remove `!is_android` from CrOS thinlto checks
>
> This was originally added for linux-chromeos builds. Now that we have
> is_chromeos_device here, it's redundant, and it unintentionally disables
> ThinLTO/CFI for ARC pieces of non-linux CrOS builds.
>
> Bug: 1062713, 1050199
> Change-Id: I27022ed72597a90ae7d2bb385729550fa8d772e6
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2108822
> Reviewed-by: Bob Haarman <inglorion@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Reviewed-by: Ben Pastene <bpastene@chromium.org>
> Commit-Queue: George Burgess <gbiv@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#751505}

Bug: 1062713, 1050199
Change-Id: I2116e2d80ebc11881deab80320b6530286c48ce3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2146994Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758998}

build/config/compiler/compiler.gni

@@ -69,10 +69,9 @@ declare_args() {
   # Use it by default on official-optimized android and Chrome OS builds, but
   # not ARC or linux-chromeos since it's been seen to not play nicely with
   # Chrome's clang. crbug.com/1033839
-  use_thin_lto =
-      is_cfi || (is_official_build && (target_os == "android" ||
-                                       (target_os == "chromeos" &&
-                                        is_chromeos_device && !is_android)))
+  use_thin_lto = is_cfi || (is_official_build &&
+                            (target_os == "android" ||
+                             (target_os == "chromeos" && is_chromeos_device)))
 
   # Performs ThinLTO code generation on Goma.
   use_goma_thin_lto = false

build/config/sanitizers/sanitizers.gni

@@ -57,7 +57,7 @@ declare_args() {
   # crbug.com/1033839. Similarly, don't use this on ARC builds.
   is_cfi = is_official_build &&
            ((target_os == "linux" && !is_chromeos && target_cpu == "x64") ||
-            (target_os == "chromeos" && is_chromeos_device && !is_android))
+            (target_os == "chromeos" && is_chromeos_device))
 
   # Enable checks for indirect function calls via a function pointer.
   # TODO(pcc): remove this when we're ready to add these checks by default.