mac: Pull a prebuilt libc++-static.a.

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 655 matching lines @@
     'name': 'clang_format_linux',
     'pattern': '.',
     'action': [ 'download_from_google_storage',
                 '--no_resume',
                 '--platform=linux*',
                 '--no_auth',
                 '--bucket', 'chromium-clang-format',
                 '-s', 'src/buildtools/linux64/clang-format.sha1',
     ],
   },
+  # Pull the prebuilt libc++ static library for mac.
+  {
+    'name': 'libcpp_mac',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=darwin',
+                '--no_auth',
+                '--bucket', 'chromium-libcpp',
+                '-s', 'src/third_party/libc++-static/libc++-static.a.sha1',
+    ],
+  },
   # Pull luci-go binaries (isolate, swarming) using checked-in hashes.
   {
     'name': 'luci-go_win',
     'pattern': '.',
     'action': [ 'download_from_google_storage',
                 '--no_resume',
                 '--platform=win32',
                 '--no_auth',
                 '--bucket', 'chromium-luci',
                 '-d', 'src/tools/luci-go/win64',
@@ skipping 121 matching lines @@
     'pattern': '.',
     'action': [
         'python',
         'src/tools/check_git_config.py',
         '--running-as-hook',
     ],
   },
 ]