Implement Web Restrictions in WebView.

components/policy/resources/policy_templates.json

Index: components/policy/resources/policy_templates.json
diff --git a/components/policy/resources/policy_templates.json b/components/policy/resources/policy_templates.json
index d3fcba6a358d9227f48b04c1ad7fad0940038395..107a301393ea8ba56405998e8e26756286fa1ed1 100644
--- a/components/policy/resources/policy_templates.json
+++ b/components/policy/resources/policy_templates.json
@@ -137,7 +137,7 @@
 #   persistent IDs for all fields (but not for groups!) are needed. These are
 #   specified by the 'id' keys of each policy. NEVER CHANGE EXISTING IDs,
 #   because doing so would break the deployed wire format!
-#   For your editing convenience: highest ID currently used: 325
+#   For your editing convenience: highest ID currently used: 327
 #
 # Placeholders:
 #   The following placeholder strings are automatically substituted:
@@ -8463,6 +8463,21 @@
 
       If SystemTimezone policy is set, it overrides this policy. In this case automatic timezone detection is completely disabled.''',
     },
+    {
+      'name': 'WebRestrictionsAuthority',
+      'id': 327,
+      'type': 'string',
+      'schema' : { 'type': 'string' },
+      'tags': [],
+      'supported_on': ['webview_android:52-'],
+      'caption': '''Set an external source of URL restrictions''',
+      'desc' : '''When this policy is set to a non-empty string the browser or WebView will read URL restrictions from the content provider with the given authority name.''',
+      'features': {
+        'dynamic_refresh': True,
+        'per_profile': False,
+      },
+      'example_value': 'com.android.chrome.SupervisedUserProvider'
+    },
   ],
   'messages': {
     # Messages that are not associated to any policies.