diff --git a/tools-webrtc/ios/client.webrtc/iOS32_Debug.json b/tools-webrtc/ios/client.webrtc/iOS32_Debug.json
index 4f86af67a0..71ab117083 100644
--- a/tools-webrtc/ios/client.webrtc/iOS32_Debug.json
+++ b/tools-webrtc/ios/client.webrtc/iOS32_Debug.json
@@ -1,15 +1,14 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"arm\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/client.webrtc/iOS32_Release.json b/tools-webrtc/ios/client.webrtc/iOS32_Release.json
index 1b5ba85d97..1fe57bc6ef 100644
--- a/tools-webrtc/ios/client.webrtc/iOS32_Release.json
+++ b/tools-webrtc/ios/client.webrtc/iOS32_Release.json
@@ -1,16 +1,14 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "dcheck_always_on=true",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=false",
     "target_cpu=\"arm\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json b/tools-webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json
index b3c0028f59..f5b02fdd19 100644
--- a/tools-webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json
+++ b/tools-webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json
@@ -1,14 +1,14 @@
 {
   "comments": [
-    "Tests for 32-bit iOS simulators."
+    "Tests for 32-bit iOS simulators.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"x86\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/client.webrtc/iOS64_Debug.json b/tools-webrtc/ios/client.webrtc/iOS64_Debug.json
index 5d7b77bc3d..d8a69c93e4 100644
--- a/tools-webrtc/ios/client.webrtc/iOS64_Debug.json
+++ b/tools-webrtc/ios/client.webrtc/iOS64_Debug.json
@@ -1,15 +1,14 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"arm64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/client.webrtc/iOS64_Release.json b/tools-webrtc/ios/client.webrtc/iOS64_Release.json
index 71242ae740..1cc6e2ae02 100644
--- a/tools-webrtc/ios/client.webrtc/iOS64_Release.json
+++ b/tools-webrtc/ios/client.webrtc/iOS64_Release.json
@@ -1,16 +1,14 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "dcheck_always_on=true",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=false",
     "target_cpu=\"arm64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json b/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json
index ad87ca184e..5c4fb8b6ba 100644
--- a/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json
+++ b/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json
@@ -1,14 +1,14 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"x64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json b/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json
index d13fa95d36..ae82e87d78 100644
--- a/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json
+++ b/tools-webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json
@@ -1,14 +1,14 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"x64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "additional_compile_targets": [ "all" ],
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json b/tools-webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
index 6c4d698035..96c4964973 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
@@ -1,14 +1,14 @@
 {
   "comments": [
-    "Tests for 32-bit iOS simulators."
+    "Tests for 32-bit iOS simulators.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"x86\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json b/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
index 25573e89a8..432768e61a 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
@@ -1,14 +1,14 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"x64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json b/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
index 0cabd24023..cf02f64f02 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
@@ -1,14 +1,14 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"x64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json b/tools-webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
index 07e2e6e30c..f1287d1f36 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
@@ -1,15 +1,14 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"arm64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios_arm64_rel.json b/tools-webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
index 1f346dd6e1..7645fd3b67 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
@@ -1,16 +1,14 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "dcheck_always_on=true",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=false",
     "target_cpu=\"arm64\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios_dbg.json b/tools-webrtc/ios/tryserver.webrtc/ios_dbg.json
index ea039ca420..bcba06f47b 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios_dbg.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios_dbg.json
@@ -1,15 +1,14 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=true",
     "target_cpu=\"arm\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/ios/tryserver.webrtc/ios_rel.json b/tools-webrtc/ios/tryserver.webrtc/ios_rel.json
index 154a3ed92a..a8601d7f92 100644
--- a/tools-webrtc/ios/tryserver.webrtc/ios_rel.json
+++ b/tools-webrtc/ios/tryserver.webrtc/ios_rel.json
@@ -1,16 +1,14 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "gn_args in this file is only read by the buildbot recipe; ",
+    "webrtc/build/mb_config.pyl contains the actual build configuration.",
+    "TODO(kjellander): remove gn_args when the recipe is updated."
   ],
   "xcode version": "8.0",
   "gn_args": [
-    "goma_dir=\"$(goma_dir)\"",
-    "dcheck_always_on=true",
-    "ios_enable_code_signing=false",
-    "is_component_build=false",
     "is_debug=false",
     "target_cpu=\"arm\"",
-    "target_os=\"ios\"",
     "use_goma=true"
   ],
   "use_analyze": false,
diff --git a/tools-webrtc/mb/mb.py b/tools-webrtc/mb/mb.py
index ea7219877c..49f681f9dc 100755
--- a/tools-webrtc/mb/mb.py
+++ b/tools-webrtc/mb/mb.py
@@ -33,8 +33,8 @@ import urllib2
 from collections import OrderedDict
 
 SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
-SRC_DIR = os.path.dirname(os.path.dirname(SCRIPT_DIR))
-sys.path = [os.path.join(SRC_DIR, 'build')] + sys.path
+CHROMIUM_SRC_DIR = os.path.dirname(os.path.dirname(SCRIPT_DIR))
+sys.path = [os.path.join(CHROMIUM_SRC_DIR, 'build')] + sys.path
 
 import gn_helpers
 
@@ -46,7 +46,7 @@ def main(args):
 
 class MetaBuildWrapper(object):
   def __init__(self):
-    self.src_dir = SRC_DIR
+    self.chromium_src_dir = CHROMIUM_SRC_DIR
     self.default_config = os.path.join(SCRIPT_DIR, 'mb_config.pyl')
     self.default_isolate_map = os.path.join(SCRIPT_DIR, 'gn_isolate_map.pyl')
     self.executable = sys.executable
@@ -619,7 +619,7 @@ class MetaBuildWrapper(object):
   def ReadIOSBotConfig(self):
     if not self.args.master or not self.args.builder:
       return {}
-    path = self.PathJoin(self.src_dir, 'tools-webrtc', 'ios',
+    path = self.PathJoin(self.chromium_src_dir, 'ios', 'build', 'bots',
                          self.args.master, self.args.builder + '.json')
     if not self.Exists(path):
       return {}
@@ -921,7 +921,7 @@ class MetaBuildWrapper(object):
           '--isolate',
           self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target)),
         ],
-        'dir': self.src_dir,
+        'dir': self.chromium_src_dir,
         'version': 1,
       },
       isolate_path + 'd.gen.json',
@@ -966,7 +966,7 @@ class MetaBuildWrapper(object):
     else:
       subdir, exe = 'win', 'gn.exe'
 
-    gn_path = self.PathJoin(self.src_dir, 'buildtools', subdir, exe)
+    gn_path = self.PathJoin(self.chromium_src_dir, 'buildtools', subdir, exe)
     return [gn_path, subcommand, path] + list(args)
 
 
@@ -1137,7 +1137,7 @@ class MetaBuildWrapper(object):
     return cmdline, extra_files
 
   def ToAbsPath(self, build_path, *comps):
-    return self.PathJoin(self.src_dir,
+    return self.PathJoin(self.chromium_src_dir,
                          self.ToSrcRelPath(build_path),
                          *comps)
 
@@ -1145,7 +1145,7 @@ class MetaBuildWrapper(object):
     """Returns a relative path from the top of the repo."""
     if path.startswith('//'):
       return path[2:].replace('/', self.sep)
-    return self.RelPath(path, self.src_dir)
+    return self.RelPath(path, self.chromium_src_dir)
 
   def ParseGYPConfigPath(self, path):
     rpath = self.ToSrcRelPath(path)
@@ -1433,12 +1433,12 @@ class MetaBuildWrapper(object):
 
   def Call(self, cmd, env=None, buffer_output=True):
     if buffer_output:
-      p = subprocess.Popen(cmd, shell=False, cwd=self.src_dir,
+      p = subprocess.Popen(cmd, shell=False, cwd=self.chromium_src_dir,
                            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                            env=env)
       out, err = p.communicate()
     else:
-      p = subprocess.Popen(cmd, shell=False, cwd=self.src_dir,
+      p = subprocess.Popen(cmd, shell=False, cwd=self.chromium_src_dir,
                            env=env)
       p.wait()
       out = err = ''
diff --git a/tools-webrtc/mb/mb_config.pyl b/tools-webrtc/mb/mb_config.pyl
index c31ba195d0..623c1d3bb3 100644
--- a/tools-webrtc/mb/mb_config.pyl
+++ b/tools-webrtc/mb/mb_config.pyl
@@ -20,13 +20,13 @@
   'masters': {
     'client.webrtc': {
       # iOS
-      'iOS32 Debug': 'ios',
-      'iOS32 Release': 'ios',
-      'iOS64 Debug': 'ios',
-      'iOS64 Release': 'ios',
-      'iOS32 Sim Debug (iOS 9.0)': 'ios',
-      'iOS64 Sim Debug (iOS 9.0)': 'ios',
-      'iOS64 Sim Debug (iOS 10.0)': 'ios',
+      'iOS32 Debug': 'ios_debug_static_bot_arm_device',
+      'iOS32 Release': 'ios_release_bot_arm_device',
+      'iOS64 Debug': 'ios_debug_static_bot_arm64_device',
+      'iOS64 Release': 'ios_release_bot_arm64_device',
+      'iOS32 Sim Debug (iOS 9.0)': 'ios_debug_static_bot_x86',
+      'iOS64 Sim Debug (iOS 9.0)': 'ios_debug_static_bot_x64',
+      'iOS64 Sim Debug (iOS 10.0)': 'ios_debug_static_bot_x64',
 
       # Mac
       'Mac64 Debug': 'debug_bot_x64',
@@ -105,13 +105,13 @@
     },
     'tryserver.webrtc': {
       # iOS
-      'ios_dbg': 'ios',
-      'ios_rel': 'ios',
-      'ios_arm64_dbg': 'ios',
-      'ios_arm64_rel': 'ios',
-      'ios32_sim_ios9_dbg': 'ios',
-      'ios64_sim_ios9_dbg': 'ios',
-      'ios64_sim_ios10_dbg': 'ios',
+      'ios_dbg': 'ios_debug_static_bot_arm_device',
+      'ios_rel': 'ios_release_bot_arm_device',
+      'ios_arm64_dbg': 'ios_debug_static_bot_arm64_device',
+      'ios_arm64_rel': 'ios_release_bot_arm64_device',
+      'ios32_sim_ios9_dbg': 'ios_debug_static_bot_x86',
+      'ios64_sim_ios9_dbg': 'ios_debug_static_bot_x64',
+      'ios64_sim_ios10_dbg': 'ios_debug_static_bot_x64',
 
       # Mac
       'mac_compile_dbg': 'debug_bot_x64',
@@ -178,6 +178,26 @@
   # 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 'release_bot' config).
   'configs': {
+    # iOS
+    'ios_debug_static_bot_arm64_device': [
+      'ios', 'gn', 'debug_static_bot', 'arm64', 'device'
+    ],
+    'ios_release_bot_arm64_device': [
+      'ios', 'gn', 'release_bot', 'arm64', 'device'
+    ],
+    'ios_debug_static_bot_arm_device': [
+      'ios', 'gn', 'debug_static_bot', 'arm', 'device'
+    ],
+    'ios_release_bot_arm_device': [
+      'ios', 'gn', 'release_bot', 'arm', 'device'
+    ],
+    'ios_debug_static_bot_x86': [
+      'ios', 'gn', 'debug_static_bot', 'x86'
+    ],
+    'ios_debug_static_bot_x64': [
+      'ios', 'gn', 'debug_static_bot', 'x64'
+    ],
+
     # Linux, Mac and Windows
     'gcc_release_bot_x64': [
       'gn', 'gcc', 'release_bot', 'x64'
@@ -225,13 +245,6 @@
       'memcheck', 'gn', 'openh264_release_bot', 'x64'
     ],
 
-    # iOS
-    # The 'ios' config is just used for auditing. iOS bots
-    # use the ios recipes and look up their GN arguments via files checked in
-    # under //tools-webrtc/ios/bots. It is an error to actually use one of these
-    # configs to generate the build files.
-    'ios': [ 'error'],
-
     # Windows
     'win_clang_debug_bot_x86': [
       'gn', 'clang', 'openh264_debug_bot', 'x86',
@@ -341,6 +354,10 @@
       'mixins': ['debug', 'static', 'minimal_symbols', 'goma'],
     },
 
+    'device': {
+      'gn_args': 'ios_enable_code_signing=false',
+    },
+
     # This mixin is used to force configs that use it to fail. It
     # is used in two cases: when we have bots that we haven't looked
     # at yet and don't know whether they need MB or not, and for bots
@@ -363,6 +380,10 @@
       'gn_args': 'use_goma=true',
     },
 
+    'ios': {
+      'gn_args': 'target_os="ios"',
+    },
+
     'libfuzzer': {
       'gn_args': 'use_libfuzzer=true',
     },
diff --git a/tools-webrtc/mb/mb_unittest.py b/tools-webrtc/mb/mb_unittest.py
index 67e1d7587d..f5c5bc272b 100755
--- a/tools-webrtc/mb/mb_unittest.py
+++ b/tools-webrtc/mb/mb_unittest.py
@@ -25,7 +25,7 @@ class FakeMBW(mb.MetaBuildWrapper):
 
     # Override vars for test portability.
     if win32:
-      self.src_dir = 'c:\\fake_src'
+      self.chromium_src_dir = 'c:\\fake_src'
       self.default_config = 'c:\\fake_src\\tools-webrtc\\mb\\mb_config.pyl'
       self.default_isolate_map = ('c:\\fake_src\\testing\\buildbot\\'
                                   'gn_isolate_map.pyl')
@@ -33,7 +33,7 @@ class FakeMBW(mb.MetaBuildWrapper):
       self.executable = 'c:\\python\\python.exe'
       self.sep = '\\'
     else:
-      self.src_dir = '/fake_src'
+      self.chromium_src_dir = '/fake_src'
       self.default_config = '/fake_src/tools-webrtc/mb/mb_config.pyl'
       self.default_isolate_map = '/fake_src/testing/buildbot/gn_isolate_map.pyl'
       self.executable = '/usr/bin/python'