Remove direct references to hermetic mac toolchain.

build/config/mac/mac_sdk.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/chrome_build.gni")
+import("//build/toolchain/toolchain.gni")
 
 # See https://bugs.chromium.org/p/webrtc/issues/detail?id=5453.
 # We can drop the rtc_require_mac_10_7_deployment flag when Chromium
 # also requires a 10.7 deployment target.
 import("//build_overrides/build.gni")
 
 declare_args() {
   # Minimum supported version of the Mac SDK.
   mac_sdk_min = mac_sdk_min_build_override
 
@@ skipping 15 matching lines @@
 # host (they are not shipped) --- this is required as Chrome on iOS is usually
 # build with the latest version of Xcode that may not ship with the version of
 # the macOS SDK used to build Chrome on mac.
 # TODO(crbug.com/635745): the check for target_os should be replaced by a
 # check that current_toolchain is default_toolchain, and the file should
 # assert that current_os is "mac" once this file is no longer included by
 # iOS toolchains.
 _verify_sdk = is_chrome_branded && is_official_build && target_os != "ios"
 
 find_sdk_args = [ "--print_sdk_path" ]
+if (!use_system_xcode) {
+  find_sdk_args += [
+    "--developer_dir",
+    hermetic_xcode_path,
+  ]
+}
 if (_verify_sdk) {
   find_sdk_args += [
     "--verify",
     mac_sdk_min,
     "--sdk_path=" + mac_sdk_path,
   ]
 } else {
   find_sdk_args += [ mac_sdk_min ]
 }
 
 # The tool will print the SDK path on the first line, and the version on the
 # second line.
 find_sdk_lines =
     exec_script("//build/mac/find_sdk.py", find_sdk_args, "list lines")
 mac_sdk_version = find_sdk_lines[1]
 if (mac_sdk_path == "") {
   mac_sdk_path = find_sdk_lines[0]
 }
 
 script_name = "//build/config/mac/sdk_info.py"
-_mac_sdk_result = exec_script(script_name, [ mac_sdk_name ], "scope")
-mac_sdk_build = _mac_sdk_result.sdk_build
+sdk_info_args = []
+if (!use_system_xcode) {
+  sdk_info_args += [
+    "--developer_dir",
+    hermetic_xcode_path,
+  ]
+}
+sdk_info_args += [ mac_sdk_name ]
+
+_mac_sdk_result = exec_script(script_name, sdk_info_args, "scope")
 xcode_version = _mac_sdk_result.xcode_version
 xcode_build = _mac_sdk_result.xcode_build
 machine_os_build = _mac_sdk_result.machine_os_build
 
 if (mac_sdk_version != mac_sdk_min_build_override &&
     exec_script("//build/check_return_value.py",
                 [
                   "test",
                   xcode_version,
                   "-ge",
                   "0730",
                 ],
                 "value") != 1) {
   print(
       "********************************************************************************")
   print(
       " WARNING: The Mac OS X SDK is incompatible with the version of Xcode. To fix,")
   print(
       "          either upgrade Xcode to the latest version or install the Mac OS X")
   print(
       "          $mac_sdk_min_build_override SDK. For more information, see https://crbug.com/620127.")
   print()
   print(" Current SDK Version:   $mac_sdk_version")
   print(" Current Xcode Version: $xcode_version ($xcode_build)")
   print(
       "********************************************************************************")
   assert(false, "SDK is incompatible with Xcode")
 }