Fix a bunch of generated file build flakes in //extensions

extensions/browser/api/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("//build/json_schema_api.gni")
+import("//extensions/common/api/schema.gni")
+
 source_set("api") {
   sources = [
     "api_resource.cc",
     "api_resource.h",
     "api_resource_manager.h",
     "async_api_function.cc",
     "async_api_function.h",
     "device_permissions_manager.cc",
     "device_permissions_manager.h",
     "device_permissions_prompt.cc",
@@ skipping 53 matching lines @@
     "//extensions/browser/api/system_storage",
     "//extensions/browser/api/test",
     "//extensions/browser/api/usb",
     "//extensions/browser/api/virtual_keyboard_private",
     "//extensions/browser/api/web_request",
   ]
 
   deps = [
     "//base:i18n",
     "//content/public/browser",
+    "//extensions/strings",
   ]
 
   if (is_chromeos) {
     public_deps += [
       "//extensions/browser/api/diagnostics",
       "//extensions/browser/api/networking_config",
       "//extensions/browser/api/vpn_provider",
       "//extensions/browser/api/webcam_private",
     ]
   }
 }
+
+json_schema_api("api_registration") {
+  sources = extensions_api_schema_files
+  impl_dir = "//extensions/browser/api"
+  bundle_registration = true
+  bundle_name = ""
+  root_namespace = extensions_api_root_namespace
+  uncompiled_sources = extensions_api_uncompiled_sources
+
+  deps = [
+    ":api",
+    "//device/serial",
+    "//extensions/common/api",
+    "//extensions/common/api/cast_channel:cast_channel_proto",
+    "//skia",
+  ]
+}