Enable use_once_callback on mojom GN rule by default

components/metrics/leak_detector/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//mojo/public/tools/bindings/mojom.gni")
 
 if (is_chromeos) {
   source_set("leak_detector") {
     sources = [
       "call_stack_manager.cc",
@@ skipping 22 matching lines @@
       ":interfaces",
       "//base",
       "//components/metrics/proto:proto",
     ]
   }
 
   mojom("interfaces") {
     sources = [
       "leak_detector.mojom",
     ]
+
+    # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
+    use_once_callback = false
   }
 
   source_set("unit_tests") {
     testonly = true
     sources = [
       "call_stack_manager_unittest.cc",
       "call_stack_table_unittest.cc",
       "leak_analyzer_unittest.cc",
       "leak_detector_impl_unittest.cc",
       "leak_detector_unittest.cc",
       "protobuf_to_mojo_converter_unittest.cc",
       "ranked_set_unittest.cc",
     ]
 
     deps = [
       ":interfaces",
       ":leak_detector",
       "//base",
       "//components/metrics/proto:proto",
       "//content/test:test_support",
       "//testing/gtest",
     ]
   }
 }