(2nd try) Add a helper class that keeps per-profile information for FileSystem API

chrome/chrome_browser.gypi

 # Copyright (c) 2010 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': '<(library)',
       'msvs_guid': '5BF908A7-68FB-4A4B-99E3-8C749F1FE4EA',
@@ skipping 1479 matching lines @@
         'browser/fav_icon_helper.cc',
         'browser/fav_icon_helper.h',
         'browser/favicon_service.cc',
         'browser/favicon_service.h',
         'browser/file_path_watcher.h',
         'browser/file_path_watcher_inotify.cc',
         'browser/file_path_watcher_mac.cc',
         'browser/file_path_watcher_win.cc',
         'browser/file_system/file_system_dispatcher_host.cc',
         'browser/file_system/file_system_dispatcher_host.h',
+        'browser/file_system/file_system_host_context.cc',
+        'browser/file_system/file_system_host_context.h',
         'browser/find_bar.h',
         'browser/find_bar_controller.cc',
         'browser/find_bar_controller.h',
         'browser/find_bar_state.h',
         'browser/find_bar_state.cc',
         'browser/find_notification_details.h',
         'browser/first_run/first_run.cc',
         'browser/first_run/first_run.h',
         'browser/first_run/first_run_mac.mm',
         'browser/first_run/first_run_win.cc',
@@ skipping 2424 matching lines @@
       ],
     },
   ],
 }
 
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 # tab-width:2
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