diff --git a/ios/clean_env.py b/ios/clean_env.py
new file mode 100755
index 000000000..548e2b92e
--- /dev/null
+++ b/ios/clean_env.py
@@ -0,0 +1,77 @@
+#!/usr/bin/python
+# Copyright (c) 2012 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.
+
+import os
+import sys
+
+def Main(argv):
+  """This is like 'env -i', but it uses a whitelist of env variables to allow
+  through to the command being run.  It attempts to strip off Xcode-added
+  values from PATH.
+  """
+  # Note: An attempt was made to do something like: env -i bash -lc '[command]'
+  # but that fails to set the things set by login (USER, etc.), so instead
+  # the only approach that seems to work is to have a whitelist.
+  env_key_whitelist = (
+    'HOME',
+    'LOGNAME',
+    # 'PATH' added below (but filtered).
+    'PWD',
+    'SHELL',
+    'TEMP',
+    'TMPDIR',
+    'USER'
+  )
+
+  # Need something to run.
+  # TODO(lliabraa): Make this output a usage string and exit (here and below).
+  assert(len(argv) > 0)
+
+  add_to_path = [];
+  first_entry = argv[0];
+  if first_entry.startswith('ADD_TO_PATH='):
+    argv = argv[1:];
+    add_to_path = first_entry.replace('ADD_TO_PATH=', '', 1).split(':')
+
+  # Still need something to run.
+  assert(len(argv) > 0)
+
+  clean_env = {}
+
+  # Pull over the whitelisted keys.
+  for key in env_key_whitelist:
+    val = os.environ.get(key, None)
+    if not val is None:
+      clean_env[key] = val
+
+  # Collect the developer dir as set via Xcode, defaulting it.
+  dev_prefix = os.environ.get('DEVELOPER_DIR', '/Developer/')
+  if dev_prefix[-1:] != '/':
+    dev_prefix += '/'
+
+  # Now pull in PATH, but remove anything Xcode might have added.
+  initial_path = os.environ.get('PATH', '')
+  filtered_chunks = \
+      [x for x in initial_path.split(':') if not x.startswith(dev_prefix)]
+  if filtered_chunks:
+    clean_env['PATH'] = ':'.join(add_to_path + filtered_chunks)
+
+  # Add any KEY=VALUE args before the command to the cleaned environment.
+  args = argv[:]
+  while '=' in args[0]:
+    (key, val) = args[0].split('=', 1)
+    clean_env[key] = val
+    args = args[1:]
+
+  # Still need something to run.
+  assert(len(args) > 0)
+
+  # Off it goes...
+  os.execvpe(args[0], args, clean_env)
+  # Should never get here, so return a distinctive, non-zero status code.
+  return 66
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))
diff --git a/ios/mac_build.gypi b/ios/mac_build.gypi
new file mode 100644
index 000000000..9a739182b
--- /dev/null
+++ b/ios/mac_build.gypi
@@ -0,0 +1,79 @@
+# Copyright (c) 2012 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.
+
+# Xcode throws an error if an iOS target depends on a Mac OS X target. So
+# any place a utility program needs to be build and run, an action is
+# used to run ninja as script to work around this.
+# Example:
+# {
+#   'target_name': 'foo',
+#   'type': 'none',
+#   'variables': {
+#     # The name of a directory used for ninja. This cannot be shared with
+#     # another mac build.
+#     'ninja_output_dir': 'ninja-foo',
+#     # The list of all the gyp files that contain the targets to run.
+#     're_run_targets': [
+#       'foo.gyp',
+#     ],
+#   },
+#   'includes': ['path_to/mac_build.gypi'],
+#   'actions': [
+#     {
+#       'action_name': 'compile foo',
+#       'inputs': [],
+#       'outputs': [],
+#       'action': [
+#         '<@(ninja_cmd)',
+#         # All the targets to build.
+#         'foo1',
+#         'foo2',
+#       ],
+#     },
+#   ],
+# }
+{
+  'variables': {
+    # Convenience variable pointing to the ninja product directory.
+    'ninja_product_dir':
+      '<(DEPTH)/xcodebuild/<(ninja_output_dir)/<(CONFIGURATION_NAME)',
+
+    # Common ninja command line flags.
+    'ninja_cmd': [
+      # Bounce through clean_env to clean up the environment so things
+      # set by the iOS build don't pollute the Mac build.
+      '<(DEPTH)/build/ios/clean_env.py',
+      # ninja must be found in the PATH.
+      'ADD_TO_PATH=<!(echo $PATH)',
+      'ninja',
+      '-C',
+      '<(ninja_product_dir)',
+    ],
+
+    # Common syntax to rerun gyp to generate the Mac projects.
+    're_run_gyp': [
+      'build/gyp_chromium',
+      # Don't use anything set for the iOS side of things.
+      '--ignore-environment',
+      # Generate for ninja
+      '--format=ninja',
+      # Generate files into xcodebuild/ninja
+      '-Goutput_dir=xcodebuild/<(ninja_output_dir)',
+      # nacl isn't in the iOS checkout, make sure it's turned off
+      '-Ddisable_nacl=1',
+      # Add a variable to handle specific cases for mac_build.
+      '-Dios_mac_build=1',
+      # Pass through the Mac SDK version.
+      '-Dmac_sdk=<(mac_sdk)',
+    ],
+
+    # Rerun gyp for each of the projects needed. This is what actually
+    # generates the projects on disk.
+    're_run_gyp_execution':
+      '<!(cd <(DEPTH) && <@(re_run_gyp) <@(re_run_targets))',
+  },
+  # Since these are used to generate things needed by other targets, make
+  # them hard dependencies so they are always built first.
+  'hard_dependency': 1,
+}