Generate better catalog C++ sources

chrome/app/mash/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("//services/catalog/public/tools/catalog.gni")
 import("//services/service_manager/public/service_manifest.gni")
 
 source_set("mash") {
   sources = [
     "mash_runner.cc",
     "mash_runner.h",
   ]
   deps = [
-    ":catalog_cpp_source",
+    ":chrome_mash_catalog",
     "//base:i18n",
     "//components/tracing:startup_tracing",
     "//content/public/common",
     "//mash/package",
     "//mash/session/public/interfaces:constants",
     "//services/catalog/public/interfaces",
     "//services/service_manager",
     "//services/service_manager/background:lib",
     "//services/service_manager/public/cpp",
     "//services/service_manager/public/cpp/standalone_service",
@@ skipping 45 matching lines @@
   if (is_linux && !is_android) {
     packaged_services += [ "//components/font_service:manifest" ]
   }
 }
 
 catalog("catalog") {
   embedded_services = [ ":mash_manifest" ]
   catalog_deps = [ "//chrome/app:catalog" ]
 }
 
-catalog_cpp_source("catalog_cpp_source") {
+catalog_cpp_source("chrome_mash_catalog") {
   catalog = ":catalog"
-  output_symbol_name = "kChromeMashCatalogContents"
+  generated_function_name = "CreateChromeMashCatalog"
 }