[Cronet] Enforce Cronet API never modified, only grown

components/cronet/android/BUILD.gn

 # Copyright 2015 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("//build/buildflag_header.gni")
 import("//build/config/android/config.gni")
 import("//build/config/android/rules.gni")
 import("//build/util/process_version.gni")
 import("//build/util/version.gni")
 import("//testing/test.gni")
@@ skipping 1417 matching lines @@
         root_build_dir),
     "--stamp",
     rebase_path(outputs[0], root_build_dir),
   ]
   deps = [
     ":cronet_api_java",
     ":cronet_impl_common_java",
     ":cronet_impl_native_java",
     ":cronet_impl_platform_java",
   ]
+  inputs = [
+    "//components/cronet/tools/update_api.py",
+  ]
+  sources = [
+    "//components/cronet/android/api.txt",
+    "//components/cronet/android/api_version.txt",
+  ]
 }
 
 group("cronet_package") {
   # Marked as testonly as it contains test-only targets too.
   testonly = true
 
   # Enforce building with ICU alternatives, crbug.com/611621.
   # Enforce that arm_use_neon==false when building for ARMv7 by
   # not including any deps in cronet_package target otherwise.
   if (use_platform_icu_alternatives &&
@@ skipping 27 matching lines @@
     deps = [
       ":cronet_package_copy_native_test_lib",
       ":cronet_package_copy_native_test_lib_unstripped",
       ":cronet_package_copy_test_assets",
       ":cronet_package_copy_test_files",
       ":cronet_package_copy_test_support_apks",
       ":repackage_extracted_test_jars",
     ]
   }
 }