Precache policy-for-extensions for device-local accounts.

components/policy/core/common/schema_map.cc

Index: components/policy/core/common/schema_map.cc
diff --git a/components/policy/core/common/schema_map.cc b/components/policy/core/common/schema_map.cc
index 90c30ee51cd4e66011fbafe961698c115ce44d8e..19898c7091449db253b1a1f01c1eba015f23fcb9 100644
--- a/components/policy/core/common/schema_map.cc
+++ b/components/policy/core/common/schema_map.cc
@@ -54,8 +54,18 @@ void SchemaMap::FilterBundle(PolicyBundle* bundle) const {
     // then its policies aren't filtered. This behavior is enabled to allow a
     // graceful update of the Legacy Browser Support extension; it'll be removed
     // in a future release. http://crbug.com/240704
-    if (!schema->valid())
+    static const char kLegacyBrowserSupportExtensionId[] =
+        "heildphpnddilhkemkielfhnkaagiabh";
+    if (it->first.domain == POLICY_DOMAIN_EXTENSIONS &&
+        it->first.component_id == kLegacyBrowserSupportExtensionId) {
       continue;
+    }
+
+    if (!schema->valid()) {
+      // Don't serve unknown policies.
+      it->second->Clear();
+      continue;
+    }
 
     PolicyMap* map = it->second;
     for (PolicyMap::const_iterator it_map = map->begin();