Use OnceCallback on Mojo interfaces in //content

content/test/BUILD.gn

Index: content/test/BUILD.gn
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index b70bc24eea0b720469b2804ee3ffabfb4172aa9f..c72402f0a21814c1c98b3450ff2cf3e365ddab24 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -463,12 +463,16 @@ mojom("content_test_mojo_bindings") {
     "../public/test/test_service.mojom",
     "test_browser_associated_interfaces.mojom",
   ]
+
+  use_once_callback = true
 }
 
 mojom("web_ui_test_mojo_bindings") {
   sources = [
     "data/web_ui_test_mojo_bindings.mojom",
   ]
+
+  use_once_callback = true
 }
 
 static_library("layouttest_support") {