mac: Roll hermetic toolchain to Xcode 8.3.2.

build/mac/should_use_hermetic_xcode.py

Index: build/mac/should_use_hermetic_xcode.py
diff --git a/build/mac/should_use_hermetic_xcode.py b/build/mac/should_use_hermetic_xcode.py
index 68e288e32f7c05f670238b0aaec893cb93a996e3..dc1b930eb0d54751fde2fe305c4686e6aca48370 100755
--- a/build/mac/should_use_hermetic_xcode.py
+++ b/build/mac/should_use_hermetic_xcode.py
@@ -3,8 +3,11 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-"""Prints "1" if Chrome targets should be built with hermetic xcode. Otherwise
-prints "0".
+"""
+Prints "1" if Chrome targets should be built with hermetic Xcode.
+Prints "2" if Chrome targets should be built with hermetic Xcode, but the OS
+version does not meet the minimum requirements of the hermetic version of Xcode.
+Otherwise prints "0".
 
 Usage:
   python should_use_hermetic_xcode.py <target_os>
@@ -13,6 +16,12 @@ Usage:
 import os
 import sys
 
+_THIS_DIR_PATH = os.path.abspath(os.path.dirname(os.path.realpath(__file__)))
+_BUILD_PATH = os.path.join(_THIS_DIR_PATH, os.pardir)
+sys.path.insert(0, _BUILD_PATH)
+
+import mac_toolchain
+
 
 def _IsCorpMachine():
   return os.path.isdir('/Library/GoogleCorpSupport/')
@@ -21,6 +30,8 @@ def _IsCorpMachine():
 def main():
   allow_corp = sys.argv[1] == 'mac' and _IsCorpMachine()
   if os.environ.get('FORCE_MAC_TOOLCHAIN') or allow_corp:
+    if not mac_toolchain.PlatformMeetsHermeticXcodeRequirements(sys.argv[1]):
+      return "2"
     return "1"
   else:
     return "0"