diff --git a/webrtc/build/PRESUBMIT.py b/webrtc/build/PRESUBMIT.py
new file mode 100644
index 0000000000..d364f862f2
--- /dev/null
+++ b/webrtc/build/PRESUBMIT.py
@@ -0,0 +1,34 @@
+# Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+
+def _CommonChecks(input_api, output_api):
+  results = []
+
+  # Validate the format of the mb_config.pyl file.
+  mb_script = input_api.os_path.join(input_api.PresubmitLocalPath(), '..',
+                                     '..', 'tools', 'mb', 'mb.py')
+  mb_config_path = input_api.os_path.join(input_api.PresubmitLocalPath(),
+                                          'mb_config.pyl')
+  cmd = [input_api.python_executable, mb_script, 'validate', '--config-file',
+         mb_config_path]
+  kwargs = {'cwd': input_api.PresubmitLocalPath()}
+  results.extend(input_api.RunTests([
+      input_api.Command(name='mb_validate',
+                        cmd=cmd, kwargs=kwargs,
+                        message=output_api.PresubmitError)]))
+
+  return results
+
+
+def CheckChangeOnUpload(input_api, output_api):
+  return _CommonChecks(input_api, output_api)
+
+
+def CheckChangeOnCommit(input_api, output_api):
+  return _CommonChecks(input_api, output_api)
diff --git a/webrtc/build/mb_config.pyl b/webrtc/build/mb_config.pyl
new file mode 100644
index 0000000000..6e352abcb6
--- /dev/null
+++ b/webrtc/build/mb_config.pyl
@@ -0,0 +1,137 @@
+# Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+# FOR DETAILS ON THIS FILE SEE THE MAIN COPY IN //tools/mb/mb_config.pyl.
+# This is configuration for standalone WebRTC bots. It is used to keep the bot
+# configurations source-side instead of in the buildbot scripts. That makes it
+# easy to try different configurations of GYP and GN in tryjob patches.
+
+{
+  # This is the list of configs that you can pass to mb; each config
+  # represents a particular combination of GYP_DEFINES/gn args that
+  # we must support. A given config *may* be platform-specific but
+  # is not necessarily so (i.e., we might have mac, win, and linux
+  # bots all using the 'gn_release_bot' config).
+  'configs': {
+    'ios_gn_debug_bot_arm64_device': ['ios', 'gn', 'debug_bot', 'arm64', 'device'],
+    'ios_gn_release_bot_arm64_device': ['ios', 'gn', 'release_bot', 'arm64', 'device'],
+    'ios_gyp_debug_bot_arm_device': ['ios', 'gyp', 'debug_bot', 'arm', 'device'],
+    'ios_gyp_release_bot_arm_device': ['ios', 'gyp', 'release_bot', 'arm', 'device'],
+    'ios_gyp_debug_bot_arm64_device': ['ios', 'gyp', 'debug_bot', 'arm64', 'device'],
+    'ios_gyp_release_bot_arm64_device': ['ios', 'gyp', 'release_bot', 'arm64', 'device'],
+    'ios_gyp_debug_bot_x86': ['ios', 'gyp', 'debug_bot', 'x86'],
+    'ios_gyp_debug_bot_x64': ['ios', 'gyp', 'release_bot', 'x64'],
+  },
+
+  # This is a dict mapping a given 'mixin' name to a dict of settings that
+  # mb should use. See //tools/mb/docs/user_guide.md for more information.
+  'mixins': {
+    'ios': {
+      'gn_args': 'target_os="ios"',
+      'gyp_defines': 'OS=ios',
+    },
+
+    'arm': {
+      'gn_args': 'target_cpu="arm"',
+      'gyp_defines': 'target_arch=arm',
+    },
+
+    'arm64': {
+      'gn_args': 'target_cpu="arm64"',
+      'gyp_defines': 'target_arch=arm64',
+    },
+
+    'debug': {
+      'gn_args': 'is_debug=true',
+    },
+
+    'debug_bot': {
+      'mixins': ['debug', 'shared', 'goma'],
+    },
+
+    'device': {
+      'gn': 'ios_enable_code_signing=false',
+      'gyp_defines': 'chromium_ios_signing=0',
+    },
+
+    'gn': {'type': 'gn'},
+
+    'goma': {
+      # The MB code will properly escape goma_dir if necessary in the GYP
+      # code path; the GN code path needs no escaping.
+      'gn_args': 'use_goma=true goma_dir="$(goma_dir)"',
+      'gyp_defines': 'use_goma=1 gomadir=$(goma_dir)',
+    },
+
+    'gyp': {'type': 'gyp'},
+
+    'release': {
+      'gn_args': 'is_debug=false',
+    },
+
+    'release_bot': {
+      'mixins': ['release', 'static', 'goma'],
+    },
+
+    'shared': {
+      'gn_args': 'is_component_build=true',
+      'gyp_defines': 'component=shared_library',
+    },
+
+    'static': {
+      'gn_args': 'is_component_build=false',
+      'gyp_defines': 'component=static_library',
+    },
+
+    'x64': {
+      'gn_args': 'target_cpu="x64"',
+      'gyp_defines': 'target_arch=x64',
+    },
+
+    'x86': {
+      'gn_args': 'target_cpu="x86"',
+      'gyp_defines': 'target_arch=ia32',
+    },
+  },
+
+  # This is a map of buildbot master names -> buildbot builder names ->
+  # config names (where each config name is a key in the 'configs' dict,
+  # above). mb uses this dict to look up which config to use for a given bot.
+  # The builders should be sorted by the order they appear in the /builders
+  # page on the buildbots, *not* alphabetically.
+  'masters': {
+    'client.webrtc': {
+      'iOS32 Debug': 'ios_gyp_debug_bot_arm_device',
+      'iOS32 Release': 'ios_gyp_release_bot_arm_device',
+      'iOS64 Debug': 'ios_gyp_debug_bot_arm64_device',
+      'iOS64 Release': 'ios_gyp_release_bot_arm64_device',
+      'iOS32 Debug Simulator': 'ios_gyp_debug_bot_x86',
+      'iOS64 Debug Simulator': 'ios_gyp_debug_bot_x64',
+    },
+    'client.webrtc.fyi': {
+      'iOS64 Debug (GN)': 'ios_gn_debug_bot_arm64_device',
+      'iOS64 Release (GN)': 'ios_gn_release_bot_arm64_device',
+    },
+    'tryserver.webrtc': {
+      'ios_dbg': 'ios_gyp_debug_bot_arm_device',
+      'ios_rel': 'ios_gyp_release_bot_arm_device',
+      'ios_arm64_dbg': 'ios_gyp_debug_bot_arm64_device',
+      'ios_arm64_rel': 'ios_gyp_release_bot_arm64_device',
+      'ios32_sim_dbg': 'ios_gyp_debug_bot_x86',
+      'ios64_sim_dbg': 'ios_gyp_debug_bot_x64',
+      'ios64_gn_dbg': 'ios_gn_debug_bot_arm64_device',
+      'ios64_gn_rel': 'ios_gn_release_bot_arm64_device',
+    },
+  },
+
+  # These lists are assumed to exist so we need them in order to be able to run
+  # the mb.py script in PRESUBMIT.py to verify our config is sane.
+  'common_dev_configs': [],
+  'private_configs': [],
+  'unsupported_configs': [],
+}