mac: Roll hermetic toolchain to Xcode 8.3.2.

Xcode 8.3.2 requires macOS 10.12+. This version of Xcode 8.3.2 has both the
10.10 and 10.12 SDKs, and builds will continue to use the 10.10 SDK.

To support machines running macOS versions < 10.12, but don't require building
targets, this CL also:
  * Does not download the hermetic toolchain if the macOS version does not
    support the toolchain version.
  * Does not allow building targets with the default hermetic toolchain if the
    macOS version does not support the toolchain version.

BUG=624049

Review-Url: https://codereview.chromium.org/2950933003
Cr-Original-Commit-Position: refs/heads/master@{#481225}
Committed: https://chromium.googlesource.com/chromium/src/+/2f19b143e444c920e643feda583e9ceb72d29c8e
Review-Url: https://codereview.chromium.org/2950933003
Cr-Commit-Position: refs/heads/master@{#481692}

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"

build/mac_toolchain.py

@@ -14,6 +14,7 @@ date:
 """
 
 import os
+import platform
 import plistlib
 import shutil
 import subprocess
@@ -24,10 +25,14 @@ import tempfile
 import urllib2
 
 # This can be changed after running /build/package_mac_toolchain.py.
-MAC_TOOLCHAIN_VERSION = '5B1008'
+MAC_TOOLCHAIN_VERSION = '8E2002'
 MAC_TOOLCHAIN_SUB_REVISION = 3
 MAC_TOOLCHAIN_VERSION = '%s-%s' % (MAC_TOOLCHAIN_VERSION,
                                    MAC_TOOLCHAIN_SUB_REVISION)
+# The toolchain will not be downloaded if the minimum OS version is not met.
+# 16 is the major version number for macOS 10.12.
+MAC_MINIMUM_OS_VERSION = 16
+
 IOS_TOOLCHAIN_VERSION = '8C1002'
 IOS_TOOLCHAIN_SUB_REVISION = 1
 IOS_TOOLCHAIN_VERSION = '%s-%s' % (IOS_TOOLCHAIN_VERSION,
@@ -44,6 +49,13 @@ TOOLCHAIN_BUILD_DIR = os.path.join(BASE_DIR, '%s_files', 'Xcode.app')
 STAMP_FILE = os.path.join(BASE_DIR, '%s_files', 'toolchain_build_revision')
 TOOLCHAIN_URL = 'gs://chrome-mac-sdk/'
 
+
+def PlatformMeetsHermeticXcodeRequirements(target_os):
+  if target_os == 'ios':
+    return True
+  return int(platform.release().split('.')[0]) >= MAC_MINIMUM_OS_VERSION
+
+
 def GetPlatforms():
   default_target_os = ["mac"]
   try:
@@ -232,6 +244,10 @@ def main():
     return 0
 
   for target_os in GetPlatforms():
+    if not PlatformMeetsHermeticXcodeRequirements(target_os):
+      print 'OS version does not support toolchain.'
+      continue
+
     if target_os == 'ios':
       default_version = IOS_TOOLCHAIN_VERSION
       toolchain_filename = 'ios-toolchain-%s.tgz'

build_overrides/build.gni

@@ -58,5 +58,8 @@ if (use_system_xcode == "") {
   _result = exec_script("//build/mac/should_use_hermetic_xcode.py",
                         [ target_os ],
                         "value")
+  assert(_result != 2,
+         "Do not allow building targets with the default" +
+             "hermetic toolchain if the minimum OS version is not met.")
   use_system_xcode = _result == 0
 }