diff --git a/infra/bots/recipe_modules/core/api.py b/infra/bots/recipe_modules/core/api.py
index 46ea4ec..e8f64cd 100644
--- a/infra/bots/recipe_modules/core/api.py
+++ b/infra/bots/recipe_modules/core/api.py
@@ -97,7 +97,7 @@
       main.revision = 'origin/master'
       main.managed = True
       m[main_name] = 'got_flutter_revision'
-      if 'Android' in self.m.vars.builder_cfg.get('extra_config', ''):
+      if 'Android' in self.m.vars.extra_tokens:
         gclient_cfg.target_os.add('android')
 
       skia_dep_path = 'src/third_party/skia'
diff --git a/infra/bots/recipe_modules/flavor/api.py b/infra/bots/recipe_modules/flavor/api.py
index a2ac1f1..93aa021 100644
--- a/infra/bots/recipe_modules/flavor/api.py
+++ b/infra/bots/recipe_modules/flavor/api.py
@@ -29,53 +29,53 @@
 
 VERSION_NONE = -1
 
-def is_android(builder_cfg):
-  return 'Android' in builder_cfg.get('extra_config', '')
+def is_android(vars_api):
+  return 'Android' in vars_api.extra_tokens
 
-def is_chromecast(builder_cfg):
-  return ('Chromecast' in builder_cfg.get('extra_config', '') or
-          'Chromecast' in builder_cfg.get('os', ''))
+def is_chromecast(vars_api):
+  return ('Chromecast' in vars_api.extra_tokens or
+          'Chromecast' in vars_api.builder_cfg.get('os', ''))
 
-def is_chromebook(builder_cfg):
-  return ('Chromebook' in builder_cfg.get('extra_config', '') or
-          'ChromeOS' in builder_cfg.get('os', ''))
+def is_chromebook(vars_api):
+  return ('Chromebook' in vars_api.extra_tokens or
+          'ChromeOS' in vars_api.builder_cfg.get('os', ''))
 
-def is_flutter(builder_cfg):
-  return 'Flutter' in builder_cfg.get('extra_config', '')
+def is_flutter(vars_api):
+  return 'Flutter' in vars_api.extra_tokens
 
-def is_ios(builder_cfg):
-  return ('iOS' in builder_cfg.get('extra_config', '') or
-          'iOS' == builder_cfg.get('os', ''))
+def is_ios(vars_api):
+  return ('iOS' in vars_api.extra_tokens or
+          'iOS' == vars_api.builder_cfg.get('os', ''))
 
-def is_pdfium(builder_cfg):
-  return 'PDFium' in builder_cfg.get('extra_config', '')
+def is_pdfium(vars_api):
+  return 'PDFium' in vars_api.extra_tokens
 
-def is_valgrind(builder_cfg):
-  return 'Valgrind' in builder_cfg.get('extra_config', '')
+def is_valgrind(vars_api):
+  return 'Valgrind' in vars_api.extra_tokens
 
 
 class SkiaFlavorApi(recipe_api.RecipeApi):
-  def get_flavor(self, builder_cfg):
+  def get_flavor(self, vars_api):
     """Return a flavor utils object specific to the given builder."""
-    if is_flutter(builder_cfg):
+    if is_flutter(vars_api):
       return flutter_flavor.FlutterFlavorUtils(self)
-    if is_chromecast(builder_cfg):
+    if is_chromecast(vars_api):
       return gn_chromecast_flavor.GNChromecastFlavorUtils(self)
-    if is_chromebook(builder_cfg):
+    if is_chromebook(vars_api):
       return gn_chromebook_flavor.GNChromebookFlavorUtils(self)
-    if is_android(builder_cfg):
+    if is_android(vars_api):
       return gn_android_flavor.GNAndroidFlavorUtils(self)
-    elif is_ios(builder_cfg):
+    elif is_ios(vars_api):
       return ios_flavor.iOSFlavorUtils(self)
-    elif is_pdfium(builder_cfg):
+    elif is_pdfium(vars_api):
       return pdfium_flavor.PDFiumFlavorUtils(self)
-    elif is_valgrind(builder_cfg):
+    elif is_valgrind(vars_api):
       return valgrind_flavor.ValgrindFlavorUtils(self)
     else:
       return gn_flavor.GNFlavorUtils(self)
 
   def setup(self):
-    self._f = self.get_flavor(self.m.vars.builder_cfg)
+    self._f = self.get_flavor(self.m.vars)
 
   def step(self, name, cmd, **kwargs):
     return self._f.step(name, cmd, **kwargs)
diff --git a/infra/bots/recipe_modules/flavor/flutter_flavor.py b/infra/bots/recipe_modules/flavor/flutter_flavor.py
index 6b95cb8..2bbf199 100644
--- a/infra/bots/recipe_modules/flavor/flutter_flavor.py
+++ b/infra/bots/recipe_modules/flavor/flutter_flavor.py
@@ -17,7 +17,7 @@
 
     flutter_dir = self.m.vars.checkout_root.join('src')
     configuration = self.m.vars.builder_cfg.get('configuration').lower()
-    extra_config = self.m.vars.builder_cfg.get('extra_config', '')
+    extra_tokens = self.m.vars.extra_tokens
     out_dir = configuration
 
     with self.m.context(cwd=flutter_dir):
@@ -31,7 +31,7 @@
       gn_args = [
           '--runtime-mode=%s' % configuration,
       ]
-      if 'Android' in extra_config:
+      if 'Android' in extra_tokens:
         gn_args.append('--android')
         out_dir = 'android_' + out_dir
 
diff --git a/infra/bots/recipe_modules/flavor/gn_android_flavor.py b/infra/bots/recipe_modules/flavor/gn_android_flavor.py
index f354611..6997541 100644
--- a/infra/bots/recipe_modules/flavor/gn_android_flavor.py
+++ b/infra/bots/recipe_modules/flavor/gn_android_flavor.py
@@ -261,7 +261,7 @@
   def compile(self, unused_target):
     compiler      = self.m.vars.builder_cfg.get('compiler')
     configuration = self.m.vars.builder_cfg.get('configuration')
-    extra_config  = self.m.vars.builder_cfg.get('extra_config', '')
+    extra_tokens  = self.m.vars.extra_tokens
     os            = self.m.vars.builder_cfg.get('os')
     target_arch   = self.m.vars.builder_cfg.get('target_arch')
 
@@ -285,14 +285,16 @@
 
     if configuration != 'Debug':
       args['is_debug'] = 'false'
-    if 'Vulkan' in extra_config:
+    if 'Vulkan' in extra_tokens:
       args['ndk_api'] = 24
       args['skia_enable_vulkan_debug_layers'] = 'false'
 
     # If an Android API level is specified, use that.
-    m = re.search(r'API(\d+)', extra_config)
-    if m and len(m.groups()) == 1:
-      args['ndk_api'] = m.groups()[0]
+    for t in extra_tokens:
+      m = re.search(r'API(\d+)', t)
+      if m and len(m.groups()) == 1:
+        args['ndk_api'] = m.groups()[0]
+        break
 
     if extra_cflags:
       args['extra_cflags'] = repr(extra_cflags).replace("'", '"')
diff --git a/infra/bots/recipe_modules/flavor/gn_flavor.py b/infra/bots/recipe_modules/flavor/gn_flavor.py
index a5aad9e..d75f9f4 100644
--- a/infra/bots/recipe_modules/flavor/gn_flavor.py
+++ b/infra/bots/recipe_modules/flavor/gn_flavor.py
@@ -56,7 +56,7 @@
     """Build Skia with GN."""
     compiler      = self.m.vars.builder_cfg.get('compiler',      '')
     configuration = self.m.vars.builder_cfg.get('configuration', '')
-    extra_config  = self.m.vars.builder_cfg.get('extra_config',  '')
+    extra_tokens  = self.m.vars.extra_tokens
     os            = self.m.vars.builder_cfg.get('os',            '')
     target_arch   = self.m.vars.builder_cfg.get('target_arch',   '')
 
@@ -90,7 +90,7 @@
       cxx  = emscripten_sdk + '/emscripten/incoming/em++'
       extra_cflags.append('-Wno-unknown-warning-option')
 
-    if 'Coverage' in extra_config:
+    if 'Coverage' in extra_tokens:
       # See https://clang.llvm.org/docs/SourceBasedCodeCoverage.html for
       # more info on using llvm to gather coverage information.
       extra_cflags.append('-fprofile-instr-generate')
@@ -101,14 +101,18 @@
     if compiler != 'MSVC' and configuration == 'Debug':
       extra_cflags.append('-O1')
 
-    if extra_config == 'Exceptions':
+    if 'Exceptions' in extra_tokens:
       extra_cflags.append('/EHsc')
-    if extra_config == 'Fast':
+    if 'Fast' in extra_tokens:
       extra_cflags.extend(['-march=native', '-fomit-frame-pointer', '-O3',
                            '-ffp-contract=off'])
-    if extra_config.startswith('SK'):
-      extra_cflags.append('-D' + extra_config)
-    if extra_config == 'MSAN':
+
+    # TODO(benjaminwagner): Same appears in compile.py to set CPPFLAGS. Are
+    # both needed?
+    if len(extra_tokens) == 1 and extra_tokens[0].startswith('SK'):
+      extra_cflags.append('-D' + extra_tokens[0])
+
+    if 'MSAN' in extra_tokens:
       extra_ldflags.append('-L' + clang_linux + '/msan')
 
     args = {}
@@ -117,16 +121,16 @@
 
     if configuration != 'Debug':
       args['is_debug'] = 'false'
-    if extra_config == 'ANGLE':
+    if 'ANGLE' in extra_tokens:
       args['skia_use_angle'] = 'true'
-    if extra_config == 'CommandBuffer':
+    if 'CommandBuffer' in extra_tokens:
       self.m.run.run_once(self.build_command_buffer)
-    if extra_config == 'MSAN':
+    if 'MSAN' in extra_tokens:
       args['skia_enable_gpu']     = 'false'
       args['skia_use_fontconfig'] = 'false'
-    if 'ASAN' in extra_config or 'UBSAN' in extra_config:
+    if 'ASAN' in extra_tokens or 'UBSAN' in extra_tokens:
       args['skia_enable_spirv_validation'] = 'false'
-    if extra_config == 'Mini':
+    if 'Mini' in extra_tokens:
       args.update({
         'is_component_build':     'true',   # Proves we can link a coherent .so.
         'is_official_build':      'true',   # No debug symbols, no tools.
@@ -139,21 +143,21 @@
         'skia_use_libwebp':       'false',
         'skia_use_zlib':          'false',
       })
-    if extra_config == 'NoGPU':
+    if 'NoGPU' in extra_tokens:
       args['skia_enable_gpu'] = 'false'
-    if extra_config == 'EmbededResouces':
+    if 'EmbededResouces' in extra_tokens:
       args['skia_embed_resoucres'] = 'true'
-    if extra_config == 'Shared':
+    if 'Shared' in extra_tokens:
       args['is_component_build'] = 'true'
-    if 'Vulkan' in extra_config and not 'Android' in extra_config:
+    if 'Vulkan' in extra_tokens and not 'Android' in extra_tokens:
       args['skia_enable_vulkan_debug_layers'] = 'false'
       if self.m.vars.is_linux:
         args['skia_vulkan_sdk'] = '"%s"' % linux_vulkan_sdk
       if 'Win' in os:
         args['skia_vulkan_sdk'] = '"%s"' % win_vulkan_sdk
-    if 'Metal' in extra_config:
+    if 'Metal' in extra_tokens:
       args['skia_use_metal'] = 'true'
-    if 'CheckGeneratedFiles' in extra_config:
+    if 'CheckGeneratedFiles' in extra_tokens:
       args['skia_compile_processors'] = 'true'
     if compiler == 'Clang' and 'Win' in os:
       args['clang_win'] = '"%s"' % self.m.vars.slave_dir.join('clang_win')
@@ -165,7 +169,7 @@
         'skia_use_icu':        'false',
         'skia_enable_gpu':     'false',
       })
-    if 'Goma' in extra_config:
+    if 'Goma' in extra_tokens:
       json_file = self._get_goma_json()
       self.m.cipd.set_service_account_credentials(json_file)
       goma_package = ('infra_internal/goma/client/%s' %
@@ -182,9 +186,11 @@
       ninja_args.extend(['-j', '100'])
 
     sanitize = ''
-    if 'SAN' in extra_config:
-      sanitize = extra_config
-    elif 'SafeStack' in extra_config:
+    for t in extra_tokens:
+      if t.endswith('SAN'):
+        sanitize = t
+    if 'SafeStack' in extra_tokens:
+      assert sanitize == ''
       sanitize = 'safe-stack'
 
     for (k,v) in {
@@ -192,7 +198,7 @@
       'cxx': cxx,
       'sanitize': sanitize,
       'target_cpu': target_arch,
-      'target_os': 'ios' if 'iOS' in extra_config else '',
+      'target_os': 'ios' if 'iOS' in extra_tokens else '',
       'win_sdk': win_toolchain + '/win_sdk' if 'Win' in os else '',
       'win_vc': win_toolchain + '/VC' if 'Win' in os else '',
     }.iteritems():
@@ -212,7 +218,7 @@
     try:
       with self.m.context(cwd=self.m.vars.skia_dir):
         self._py('fetch-gn', self.m.vars.skia_dir.join('bin', 'fetch-gn'))
-        if 'CheckGeneratedFiles' in extra_config:
+        if 'CheckGeneratedFiles' in extra_tokens:
           env['PATH'] = '%s:%%(PATH)s' % self.m.vars.skia_dir.join('bin')
           self._py(
               'fetch-clang-format',
@@ -236,11 +242,11 @@
 
   def copy_extra_build_products(self, swarming_out_dir):
     configuration = self.m.vars.builder_cfg.get('configuration', '')
-    extra_config  = self.m.vars.builder_cfg.get('extra_config',  '')
+    extra_tokens  = self.m.vars.extra_tokens
     os            = self.m.vars.builder_cfg.get('os',            '')
 
     win_vulkan_sdk = str(self.m.vars.slave_dir.join('win_vulkan_sdk'))
-    if 'Win' in os and extra_config == 'Vulkan':
+    if 'Win' in os and 'Vulkan' in extra_tokens:
       self.m.run.copy_build_products(
           win_vulkan_sdk,
           swarming_out_dir.join('out', configuration + '_x64'))
@@ -254,7 +260,7 @@
 
     slave_dir = self.m.vars.slave_dir
     clang_linux = str(slave_dir.join('clang_linux'))
-    extra_config = self.m.vars.builder_cfg.get('extra_config', '')
+    extra_tokens = self.m.vars.extra_tokens
 
     if self.m.vars.is_linux:
       if (self.m.vars.builder_cfg.get('cpu_or_gpu', '') == 'GPU'
@@ -268,31 +274,31 @@
         env['LIBGL_DRIVERS_PATH'] = str(dri_path)
         env['VK_ICD_FILENAMES'] = str(dri_path.join('intel_icd.x86_64.json'))
 
-      if 'Vulkan' in extra_config:
+      if 'Vulkan' in extra_tokens:
         path.append(slave_dir.join('linux_vulkan_sdk', 'bin'))
         ld_library_path.append(slave_dir.join('linux_vulkan_sdk', 'lib'))
 
-    if 'SAN' in extra_config:
+    if any('SAN' in t for t in extra_tokens):
       # Sanitized binaries may want to run clang_linux/bin/llvm-symbolizer.
       path.append(clang_linux + '/bin')
     elif self.m.vars.is_linux:
       cmd = ['catchsegv'] + cmd
 
-    if 'ASAN' == extra_config or 'UBSAN' in extra_config:
+    if 'ASAN' in extra_tokens or 'UBSAN' in extra_tokens:
       env[ 'ASAN_OPTIONS'] = 'symbolize=1 detect_leaks=1'
       env[ 'LSAN_OPTIONS'] = 'symbolize=1 print_suppressions=1'
       env['UBSAN_OPTIONS'] = 'symbolize=1 print_stacktrace=1'
 
-    if 'MSAN' == extra_config:
+    if 'MSAN' in extra_tokens:
       # Find the MSAN-built libc++.
       ld_library_path.append(clang_linux + '/msan')
 
-    if 'TSAN' == extra_config:
+    if 'TSAN' in extra_tokens:
       # We don't care about malloc(), fprintf, etc. used in signal handlers.
       # If we're in a signal handler, we're already crashing...
       env['TSAN_OPTIONS'] = 'report_signal_unsafe=0'
 
-    if 'Coverage' in extra_config:
+    if 'Coverage' in extra_tokens:
       # This is the output file for the coverage data. Just running the binary
       # will produce the output. The output_file is in the swarming_out_dir and
       # thus will be an isolated output of the Test step.
diff --git a/infra/bots/recipe_modules/vars/api.py b/infra/bots/recipe_modules/vars/api.py
index f43e6a9..92a61c2 100644
--- a/infra/bots/recipe_modules/vars/api.py
+++ b/infra/bots/recipe_modules/vars/api.py
@@ -120,6 +120,13 @@
     arch = (self.builder_cfg.get('arch') or self.builder_cfg.get('target_arch'))
     if ('Win' in self.builder_cfg.get('os', '') and arch == 'x86_64'):
       self.configuration += '_x64'
+    self.extra_tokens = []
+    if len(self.builder_cfg.get('extra_config', '')) > 0:
+      if self.builder_cfg['extra_config'].startswith('SK'):
+        assert self.builder_cfg['extra_config'].isupper()
+        self.extra_tokens = [self.builder_cfg['extra_config']]
+      else:
+        self.extra_tokens = self.builder_cfg['extra_config'].split('_')
 
     self.default_env.update({'SKIA_OUT': self.skia_out,
                              'BUILDTYPE': self.configuration})
@@ -221,4 +228,3 @@
 ''',
           stdout=self.m.raw_io.output()).stdout.rstrip()
     return self._swarming_task_id
-
diff --git a/infra/bots/recipe_modules/vars/examples/full.expected/Build-Debian9-Clang-x86_64-Release-SKNX_NO_SIMD.json b/infra/bots/recipe_modules/vars/examples/full.expected/Build-Debian9-Clang-x86_64-Release-SKNX_NO_SIMD.json
new file mode 100644
index 0000000..4594f9e
--- /dev/null
+++ b/infra/bots/recipe_modules/vars/examples/full.expected/Build-Debian9-Clang-x86_64-Release-SKNX_NO_SIMD.json
@@ -0,0 +1,35 @@
+[
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "import os\nprint os.environ.get('SWARMING_BOT_ID', '')\n"
+    ],
+    "name": "get swarming bot id",
+    "stdout": "/path/to/tmp/",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@python.inline@import os@@@",
+      "@@@STEP_LOG_LINE@python.inline@print os.environ.get('SWARMING_BOT_ID', '')@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "import os\nprint os.environ.get('SWARMING_TASK_ID', '')\n"
+    ],
+    "name": "get swarming task id",
+    "stdout": "/path/to/tmp/",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@python.inline@import os@@@",
+      "@@@STEP_LOG_LINE@python.inline@print os.environ.get('SWARMING_TASK_ID', '')@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/bots/recipe_modules/vars/examples/full.py b/infra/bots/recipe_modules/vars/examples/full.py
index 5eff062..b1a0af9 100644
--- a/infra/bots/recipe_modules/vars/examples/full.py
+++ b/infra/bots/recipe_modules/vars/examples/full.py
@@ -22,6 +22,7 @@
 
 
 TEST_BUILDERS = [
+  'Build-Debian9-Clang-x86_64-Release-SKNX_NO_SIMD',
   'Build-Debian9-GCC-x86_64-Release-Flutter_Android',
   'Build-Debian9-GCC-x86_64-Release-PDFium',
   'Build-Mac-Clang-x86_64-Debug-CommandBuffer',
diff --git a/infra/bots/recipes/compile.py b/infra/bots/recipes/compile.py
index d628a00..25c8a95 100644
--- a/infra/bots/recipes/compile.py
+++ b/infra/bots/recipes/compile.py
@@ -26,16 +26,18 @@
   return ['most']
 
 
-def get_extra_env_vars(builder_dict):
+def get_extra_env_vars(vars_api):
   env = {}
-  if builder_dict.get('compiler') == 'Clang':
+  if vars_api.builder_cfg.get('compiler') == 'Clang':
     env['CC'] = '/usr/bin/clang'
     env['CXX'] = '/usr/bin/clang++'
 
   # SKNX_NO_SIMD, SK_USE_DISCARDABLE_SCALEDIMAGECACHE, etc.
-  extra_config = builder_dict.get('extra_config', '')
-  if extra_config.startswith('SK') and extra_config.isupper():
-    env['CPPFLAGS'] = '-D' + extra_config
+  # TODO(benjaminwagner): Same appears in gn_flavor.py to set extra_cflags. Are
+  # both needed?
+  if (len(vars_api.extra_tokens) == 1 and
+      vars_api.extra_tokens[0].startswith('SK')):
+    env['CPPFLAGS'] = '-D' + vars_api.extra_tokens[0]
 
   return env
 
@@ -43,7 +45,7 @@
 def RunSteps(api):
   api.core.setup()
 
-  env = get_extra_env_vars(api.vars.builder_cfg)
+  env = get_extra_env_vars(api.vars)
   build_targets = build_targets_from_builder_dict(api.vars.builder_cfg)
 
   try:
diff --git a/infra/bots/recipes/perf.py b/infra/bots/recipes/perf.py
index 99e68af..b9be776 100644
--- a/infra/bots/recipes/perf.py
+++ b/infra/bots/recipes/perf.py
@@ -292,8 +292,7 @@
         args.extend([k, api.vars.builder_cfg[k]])
 
   # See skia:2789.
-  extra_config_parts = api.vars.builder_cfg.get('extra_config', '').split('_')
-  if 'AbandonGpuContext' in extra_config_parts:
+  if 'AbandonGpuContext' in api.vars.extra_tokens:
     args.extend(['--abandonGpuContext'])
 
   api.run(api.flavor.step, target, cmd=args,
diff --git a/infra/bots/recipes/test.py b/infra/bots/recipes/test.py
index 53aac01..53c2610 100644
--- a/infra/bots/recipes/test.py
+++ b/infra/bots/recipes/test.py
@@ -859,12 +859,11 @@
   args.extend(dm_flags(api, api.vars.builder_name))
 
   # See skia:2789.
-  extra_config_parts = api.vars.builder_cfg.get('extra_config', '').split('_')
-  if 'AbandonGpuContext' in extra_config_parts:
+  if 'AbandonGpuContext' in api.vars.extra_tokens:
     args.append('--abandonGpuContext')
-  if 'PreAbandonGpuContext' in extra_config_parts:
+  if 'PreAbandonGpuContext' in api.vars.extra_tokens:
     args.append('--preAbandonGpuContext')
-  if 'ReleaseAndAbandonGpuContext' in extra_config_parts:
+  if 'ReleaseAndAbandonGpuContext' in api.vars.extra_tokens:
     args.append('--releaseAndAbandonGpuContext')
 
   api.run(api.flavor.step, 'dm', cmd=args, abort_on_failure=False)