diff --git content/browser/child_process_security_policy_impl.cc content/browser/child_process_security_policy_impl.cc
index ca111c5b80ee..35e734fe6a54 100644
--- content/browser/child_process_security_policy_impl.cc
+++ content/browser/child_process_security_policy_impl.cc
@@ -1498,6 +1498,16 @@ bool ChildProcessSecurityPolicyImpl::CanAccessDataForOrigin(
         // DeclarativeApiTest.PersistRules.
         if (actual_process_lock.SchemeIs(url::kDataScheme))
           return true;
+
+        // Allow other schemes that are non-standard, non-local and WebSafe.
+        if (actual_process_lock.is_valid() &&
+            !actual_process_lock.IsStandard() &&
+            !base::Contains(url::GetLocalSchemes(),
+                            actual_process_lock.scheme_piece()) &&
+            base::Contains(schemes_okay_to_request_in_any_process_,
+                           actual_process_lock.scheme_piece())) {
+          return true;
+        }
       }
 
       failure_reason = "lock_mismatch";