Extract external file systems handling from isolated context.

chrome/browser/chromeos/extensions/file_browser_private_api.cc

 // Copyright (c) 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.
 
 #include "chrome/browser/chromeos/extensions/file_browser_private_api.h"
 
 #include <sys/stat.h>
 #include <sys/statvfs.h>
 #include <sys/types.h>
 #include <utime.h>
@@ skipping 497 matching lines @@
     fileapi::ExternalFileSystemMountPointProvider* provider =
         file_system_context_->external_provider();
     if (!provider)
       return false;
 
     // Grant full access to File API from this component extension.
     provider->GrantFullAccessToExtension(extension_->id());
 
     // Grant R/W file permissions to the renderer hosting component
     // extension for all paths exposed by our local file system provider.
-    std::vector<FilePath> root_dirs = provider->GetRootDirectories();
+    std::vector<FilePath> root_dirs = provider->GetRootDirectories(true);
     for (size_t i = 0; i < root_dirs.size(); ++i) {
       ChildProcessSecurityPolicy::GetInstance()->GrantPermissionsForFile(
           child_id_, root_dirs[i],
           file_handler_util::GetReadWritePermissions());
     }
     return true;
   }
 
   RequestLocalFileSystemFunction* function_;
   scoped_refptr<fileapi::FileSystemContext> file_system_context_;
@@ skipping 2484 matching lines @@
   // Keep the refcount until the zipping is complete on utility process.
   AddRef();
   return true;
 }
 
 void ZipSelectionFunction::OnZipDone(bool success) {
   SetResult(new base::FundamentalValue(success));
   SendResponse(true);
   Release();
 }