Make sure key::kEnableWebBasedSignin policy also turns on command line arg

components/policy/resources/policy_templates.json

 {
 # policy_templates.json - Metafile for policy templates
 #
 # The content of this file is evaluated as a Python expression.
 #
 # This file is used as input to generate the following policy templates:
 # ADM, ADMX+ADML, MCX/plist and html documentation.
 #
 # Policy templates are user interface definitions or documents about the
 # policies that can be used to configure Chrome. Each policy is a name-value
@@ skipping 1177 matching lines @@
       'desc': '''This policy is deprecated, consider using SyncDisabled instead.
 
       Allows the user to sign in to <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>.
 
       If you set this policy, you can configure whether a user is allowed to sign in to <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>. Setting this policy to 'False' will prevent apps and extensions that use the chrome.identity API from functioning, so you may want to use SyncDisabled instead.''',
     },
     {
       'name': 'EnableWebBasedSignin',
       'type': 'main',
       'schema': { 'type': 'boolean' },
-      'supported_on': ['chrome.*:35-'],
+      'supported_on': ['chrome.*:35-42'],
       'features': {
         'dynamic_refresh': False,
         'per_profile': False,
       },
+      'deprecated': True,
       'example_value': False,
       'id': 265,
       'caption': '''Enables the old web-based signin''',
       'desc': '''Enables the old web-based signin flow.
 
+      This setting should no longer be needed as of Chrome 41 and support will be removed entirely in Chrome 43.
+      This setting will be renamed in Chrome 42 as part of the deprecation process.
+
       This setting is useful for enterprise customers who are using SSO solutions that are not compatible with the new inline signin flow yet.
       If you enable this setting, the old web-based signin flow would be used.
       If you disable this setting or leave it not set, the new inline signin flow would be used by default. Users may still enable the old web-based signin flow through the command line flag --enable-web-based-signin.
 
       The experimental setting will be removed in the future when the inline signin fully supports all SSO signin flows.''',
     },
     {
       'name': 'UserDataDir',
       'type': 'string',
       'schema': { 'type': 'string' },
@@ skipping 6086 matching lines @@
       'desc': '''Text appended in parentheses next to the policies top-level container to indicate that those policies are of the Recommended level''',
       'text': 'Default Settings (users can override)',
     },
     'doc_complex_policies_on_windows': {
       'desc': '''Text pointing the user to a help article for complex policies on Windows''',
       'text': '''encoded as a JSON string, for details see <ph name="COMPLEX_POLICIES_URL">http://www.chromium.org/administrators/complex-policies-on-windows<ex>http://www.chromium.org/administrators/complex-policies-on-windows</ex></ph>''',
     },
   },
   'placeholders': [],
 }