reland #3: Set mac_min_sdk=10.10 on chromium.mac bots.

scripts/slave/recipe_modules/chromium_tests/chromium_mac.py

 # 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.
 
 from . import steps
 
 SPEC = {
   'settings': {
     'build_gs_bucket': 'chromium-mac-archive',
     # WARNING: src-side runtest.py is only tested with chromium CQ builders.
     # Usage not covered by chromium CQ is not supported and can break
     # without notice.
     'src_side_runtest_py': True,
   },
   'builders': {
     'Mac Builder': {
       'chromium_config': 'chromium',
-      'chromium_apply_config': ['ninja_confirm_noop'],
+      'chromium_apply_config': ['ninja_confirm_noop', 'chromium_mac_sdk_10_10'],
       'gclient_config': 'chromium',
       'chromium_config_kwargs': {
         'BUILD_CONFIG': 'Release',
         'TARGET_BITS': 64,
       },
       'bot_type': 'builder',
       'compile_targets': [
         'chromium_builder_tests',
       ],
       'testing': {
@@ skipping 98 matching lines @@
         steps.generate_gtest,
         steps.generate_script,
       ],
       'enable_swarming': True,
       'testing': {
         'platform': 'mac',
       },
     },
     'Mac Builder (dbg)': {
       'chromium_config': 'chromium',
-      'chromium_apply_config': ['ninja_confirm_noop'],
+      'chromium_apply_config': ['ninja_confirm_noop', 'chromium_mac_sdk_10_10'],
       'gclient_config': 'chromium',
       'chromium_config_kwargs': {
         'BUILD_CONFIG': 'Debug',
         'TARGET_BITS': 64,
       },
       'bot_type': 'builder',
       'compile_targets': [
         'chromium_builder_tests',
       ],
       'testing': {
@@ skipping 36 matching lines @@
         steps.generate_gtest,
         steps.generate_script,
       ],
       'enable_swarming': True,
       'testing': {
         'platform': 'mac',
       },
     },
   },
 }