DevTools: move FileSystemMapping under persistence/ module

third_party/WebKit/Source/devtools/front_end/persistence/Automapping.js

Index: third_party/WebKit/Source/devtools/front_end/persistence/Automapping.js
diff --git a/third_party/WebKit/Source/devtools/front_end/persistence/Automapping.js b/third_party/WebKit/Source/devtools/front_end/persistence/Automapping.js
index 87c40a11d4da99d8cb2341a04f64e4f83e15347d..fc4196a8d4884f4891d55185b6962f4a0c628f47 100644
--- a/third_party/WebKit/Source/devtools/front_end/persistence/Automapping.js
+++ b/third_party/WebKit/Source/devtools/front_end/persistence/Automapping.js
@@ -1,7 +1,9 @@
 // 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.
+
 /**
+ * @implements {Persistence.MappingSystem}
  * @unrestricted
  */
 Persistence.Automapping = class {
@@ -300,6 +302,9 @@ Persistence.Automapping = class {
     });
   }
 
+  /**
+   * @override
+   */
   dispose() {
     if (this._disposed)
       return;