Move chrome.fileSystem interface and bindings to //extensions

extensions/common/api/_api_features.json

 // Copyright 2014 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.
 
 // This features file defines extension APIs implemented under src/extensions.
 // See chrome/common/extensions/api/_features.md to understand this file, as
 // well as feature.h, simple_feature.h, and feature_provider.h.
 //
 // Note that specifying "web_page", "blessed_web_page", or "all" as a context
 // type will require manually updating chrome/renderer/resources/dispatcher.cc.
@@ skipping 155 matching lines @@
       ]
     }
   ],
   "events": {
     "internal": true,
     "channel": "stable",
     "extension_types": ["platform_app", "extension"],
     "contexts": "all",
     "matches": ["<all_urls>"]
   },
+  "fileSystem": {
+    "dependencies": ["permission:fileSystem"],
+    "contexts": ["blessed_extension"]
+  },
   "guestViewInternal": [
     {
       "internal": true,
       "channel": "stable",
       "contexts": ["blessed_extension"]
     }, {
       "internal": true,
       "channel": "stable",
       "contexts": ["webui"],
       "matches": [
@@ skipping 352 matching lines @@
   }, {
     "channel": "stable",
     "contexts": ["webui"],
     "matches": [
       "chrome://chrome-signin/*",
       "chrome://media-router/*",
       "chrome://oobe/*"
     ]
   }]
 }