Revert "mac: Switch to Xcode 16.0 16A242d with macOS SDK 15.0 24A336"

This reverts commit fbc74102ad.

Reason for revert: suspected cause of tree closure
https://ci.chromium.org/ui/p/chromium/builders/ci/Mac%20ASan%2064%20Builder/201161/blamelist

Original change's description:
> mac: Switch to Xcode 16.0 16A242d with macOS SDK 15.0 24A336
>
> FOR CHECKIN
> FOR CHICKEN
> PARA POLLO
> POUR LE POULET
> 🐣
>
> Bug: 367439535
> Change-Id: I13c4849eddb458b76d973dcc059c7043b63b4245
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5868532
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Commit-Queue: Mark Mentovai <mark@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1356474}

Bug: 367439535
Change-Id: I363c1af2dd9b7a732a5887ed2233d7d3caa69f99
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5867385
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Nicolás Peña <npm@chromium.org>
Owners-Override: Nicolás Peña <npm@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1356504}

build/config/mac/mac_sdk.gni

@@ -45,12 +45,12 @@ declare_args() {
   # The SDK version used when making official builds. This is a single exact
   # version, not a minimum. If this version isn't available official builds
   # will fail.
-  mac_sdk_official_version = "15.0"
+  mac_sdk_official_version = "14.0"
 
   # The SDK build version used when making official builds.  This is a single
   # exact version found at "System/Library/CoreServices/SystemVersion.plist"
   # inside the SDK.
-  mac_sdk_official_build_version = "24A336"
+  mac_sdk_official_build_version = "23A334"
 
   # Production builds should use hermetic Xcode. If you want to do production
   # builds with system Xcode to test new SDKs, set this.

build/mac_toolchain.py

@@ -33,14 +33,16 @@ def LoadPList(path):
     return plistlib.load(f)
 
 
-# This contains binaries from Xcode 16.0 16A242d along with the macOS 15.0 SDK
+# This contains binaries from Xcode 15.0 15A240d along with the macOS 14.0 SDK
-# (24A336). To build these packages, see comments in build/xcode_binaries.yaml.
+# (14.0 23A334). To build these packages, see comments in
+# build/xcode_binaries.yaml
 # To update the version numbers, open Xcode's "About Xcode" for the first number
-# and run `xcrun --show-sdk-build-version` for the second. To update the _TAG,
+# and run `xcrun --show-sdk-build-version` for the second.
-# use the output of the `cipd create` command mentioned in xcode_binaries.yaml.
+# To update the _TAG, use the output of the `cipd create` command mentioned in
+# xcode_binaries.yaml.
 
 MAC_BINARIES_LABEL = 'infra_internal/ios/xcode/xcode_binaries/mac-amd64'
-MAC_BINARIES_TAG = 'Frm7sYyjocgTMac6vFlyzenLZUQVWNZ3J2XhsIeJB0YC'
+MAC_BINARIES_TAG = 'dC_BLs9U850OLk8m4V7yxysPhP-ixJ2b5c7hVm8B7tIC'
 
 # The toolchain will not be downloaded if the minimum OS version is not met. 19
 # is the major version number for macOS 10.15. Xcode 15.0 only runs on macOS

build/xcode_binaries.yaml

@@ -22,7 +22,7 @@ root: "xcode_binaries"
 data:
   - dir: Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/
   - dir: Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/share/bison
-  - dir: Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/metal
+  - dir: Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/metal/macos
   - file: Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/air-lld
   - file: Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/bison
   - file: Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/gm4