Move chrome.fileSystem interface and bindings to //extensions

chrome/common/extensions/api/_api_features.json

 // Copyright 2012 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/chrome.
 // 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 457 matching lines @@
   },
   "fileManagerPrivate": {
     "dependencies": ["permission:fileManagerPrivate"],
     "contexts": ["blessed_extension"]
   },
   "fileManagerPrivateInternal": {
     "internal": true,
     "dependencies": ["permission:fileManagerPrivate"],
     "contexts": ["blessed_extension"]
   },
-  "fileSystem": {
-    "dependencies": ["permission:fileSystem"],
-    "contexts": ["blessed_extension"]
-  },
   "fileSystemProvider": {
     "dependencies": ["permission:fileSystemProvider"],
     "contexts": ["blessed_extension"]
   },
   "fileSystemProviderInternal": {
     "internal": true,
     "dependencies": ["permission:fileSystemProvider"],
     "contexts": ["blessed_extension"]
   },
   "firstRunPrivate": {
@@ skipping 353 matching lines @@
     "dependencies": ["api:tabs"],
     "contexts": ["blessed_extension"]
   }, {
     "channel": "stable",
     "contexts": ["webui"],
     "matches": [
       "chrome://bookmarks/*"
     ]
   }]
 }