Query sdk-platform-path in build/config/mac/sdk_info.py.

build/config/ios/ios_sdk.gni

 # Copyright 2015 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.
 
 declare_args() {
   # SDK path to use. When empty this will use the default SDK based on the
   # value of use_ios_simulator.
   ios_sdk_path = ""
   ios_sdk_name = ""
   ios_sdk_version = ""
   ios_sdk_platform = ""
+  ios_sdk_platform_path = ""
   xcode_version = ""
   xcode_build = ""
   machine_os_build = ""
 
   use_ios_simulator = current_cpu == "x86" || current_cpu == "x64"
 
   # Version of iOS that we're targeting.
   ios_deployment_target = "9.0"
 
   # The iOS Code signing identity to use
@@ skipping 46 matching lines @@
     ios_sdk_name = "iphonesimulator"
     ios_sdk_platform = "iPhoneSimulator"
   } else {
     ios_sdk_name = "iphoneos"
     ios_sdk_platform = "iPhoneOS"
   }
   _ios_sdk_result =
       exec_script("//build/config/mac/sdk_info.py", [ ios_sdk_name ], "scope")
   ios_sdk_path = _ios_sdk_result.sdk_path
   ios_sdk_version = _ios_sdk_result.sdk_version
+  ios_sdk_platform_path = _ios_sdk_result.sdk_platform_path
   ios_sdk_build = _ios_sdk_result.sdk_build
   xcode_version = _ios_sdk_result.xcode_version
   xcode_build = _ios_sdk_result.xcode_build
   machine_os_build = _ios_sdk_result.machine_os_build
   if (use_ios_simulator) {
     # This is weird, but Xcode sets DTPlatformBuild to an empty field for
     # simulator builds.
     ios_platform_build = ""
   } else {
     ios_platform_build = ios_sdk_build
@@ skipping 13 matching lines @@
     ios_code_signing_identity = _ios_identities[0]
   }
 
   if (ios_code_signing_identity == "") {
     print("Tried to prepare a device build without specifying a code signing")
     print("identity and could not detect one automatically either.")
     print("TIP: Simulator builds don't require code signing...")
     assert(false)
   }
 }