Add new BrowserForceSigninEnabeld policy option with future:true flag.

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 7938 matching lines @@
       },
       'example_value': True,
       'id': 276,
       'caption': '''Enable add person in profile manager''',
       'tags': [],
       'desc': '''If this policy is set to true or not configured, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will allow Add Person from the user manager.
 
       If this policy is set to false, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will not allow creation of new profiles from the profile manager.''',
     },
     {
+      'name': 'ForceBrowserSignin',
+      'type': 'main',
+      'future': True,
+      'schema': { 'type': 'boolean' },
+      'supported_on': ['chrome.*:55-'],
+      'features': {
+        'dynamic_refresh': False,
+        'per_profile': False,
+      },
+      'example_value': False,
+      'id': 346,
+      'caption': '''Enables force sign in for <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>.''',
+      'tags': [],
+      'desc': '''If this policy is set to true, user has to sign in to <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> with his or her profile before using the browser. And the default value of BrowserGuestModeEnabled will be set to false.
+
+      If this policy is set to false or not configured, user can use the browser without sign in to <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>.''',
+    },
+    {
       'name': 'SSLVersionMin',
       'type': 'string-enum',
       'schema': {
         'type': 'string',
         'enum': [
           'ssl3',
           'tls1',
           'tls1.1',
           'tls1.2',
         ],
@@ skipping 1123 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">https://www.chromium.org/administrators/complex-policies-on-windows<ex>https://www.chromium.org/administrators/complex-policies-on-windows</ex></ph>''',
     },
   },
   'placeholders': [],
 }