mac/arm: Disable -Wmax-tokens.

-Wmax-tokens coverage on mac/intel should be sufficient for now.
We just need to remember to switch this when we turn down the intel
mac bots in a decade or so.

../../content/public/browser/content_browser_client.cc:12:31: error:
   the number of preprocessor source tokens (902784) exceeds this token limit (860000) [-Werror,-Wmax-tokens]
    #pragma clang max_tokens_here 860000
                                  ^

Bug: 1098899
Change-Id: I5ddefd30b39cffb0a9aacd2838847c9c06d3fe93
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2281319
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#785300}

build/config/compiler/BUILD.gn

@@ -145,7 +145,8 @@ declare_args() {
   # so only enable them by default for mainstream build configs.
   enable_wmax_tokens =
       !is_official_build &&
-      (is_mac || (is_linux && !is_chromeos && target_cpu == "x64") ||
+      ((is_mac && target_cpu == "x64") ||
+       (is_linux && !is_chromeos && target_cpu == "x64") ||
        (is_win && target_cpu == "x86") || (is_win && target_cpu == "x64") ||
        (is_android && target_cpu == "arm") ||
        (is_android && target_cpu == "arm64"))