Revert of Move more sources from modules.gypi to subdirectories.

third_party/WebKit/Source/modules/app_banner/BUILD.gn

Index: third_party/WebKit/Source/modules/app_banner/BUILD.gn
diff --git a/third_party/WebKit/Source/modules/app_banner/BUILD.gn b/third_party/WebKit/Source/modules/app_banner/BUILD.gn
deleted file mode 100644
index 7ba856a906b57285dd2740319b53af2e0af048c8..0000000000000000000000000000000000000000
--- a/third_party/WebKit/Source/modules/app_banner/BUILD.gn
+++ /dev/null
@@ -1,18 +0,0 @@
-# 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("//third_party/WebKit/Source/modules/modules.gni")
-
-blink_modules_sources("app_banner") {
-  sources = [
-    "AppBannerCallbacks.cpp",
-    "AppBannerCallbacks.h",
-    "AppBannerController.cpp",
-    "AppBannerController.h",
-    "AppBannerPromptResult.cpp",
-    "AppBannerPromptResult.h",
-    "BeforeInstallPromptEvent.cpp",
-    "BeforeInstallPromptEvent.h",
-  ]
-}