DevTools: move FileSystemMapping under persistence/ module

third_party/WebKit/Source/devtools/BUILD.gn

Index: third_party/WebKit/Source/devtools/BUILD.gn
diff --git a/third_party/WebKit/Source/devtools/BUILD.gn b/third_party/WebKit/Source/devtools/BUILD.gn
index c88c0dc8dd6cac9685bab6f04e88f3641e54efde..a33859ad5c53010a4dc0ca33b73ce9453182a1a6 100644
--- a/third_party/WebKit/Source/devtools/BUILD.gn
+++ b/third_party/WebKit/Source/devtools/BUILD.gn
@@ -376,6 +376,9 @@ all_devtools_files = [
   "front_end/perf_ui/TimelineOverviewPane.js",
   "front_end/persistence/Automapping.js",
   "front_end/persistence/DefaultMapping.js",
+  "front_end/persistence/editFileSystemView.css",
+  "front_end/persistence/EditFileSystemView.js",
+  "front_end/persistence/FileSystemMapping.js",
   "front_end/persistence/FileSystemWorkspaceBinding.js",
   "front_end/persistence/Persistence.js",
   "front_end/persistence/PersistenceUtils.js",
@@ -506,8 +509,6 @@ all_devtools_files = [
   "front_end/security/SecurityPanel.js",
   "front_end/security/sidebar.css",
   "front_end/services/ServiceManager.js",
-  "front_end/settings/editFileSystemView.css",
-  "front_end/settings/EditFileSystemView.js",
   "front_end/settings/frameworkBlackboxSettingsTab.css",
   "front_end/settings/FrameworkBlackboxSettingsTab.js",
   "front_end/settings/module.json",
@@ -715,7 +716,6 @@ all_devtools_files = [
   "front_end/utility_shared_worker/TempStorage.js",
   "front_end/worker_service/ServiceDispatcher.js",
   "front_end/workspace/FileManager.js",
-  "front_end/workspace/FileSystemMapping.js",
   "front_end/workspace/IsolatedFileSystem.js",
   "front_end/workspace/IsolatedFileSystemManager.js",
   "front_end/workspace/module.json",