Make isolated file system works for a device root (e.g. X:\\)

chrome/browser/media_gallery/media_file_system_registry.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.
 
 // MediaFileSystemRegistry implementation.
 
 #include "chrome/browser/media_gallery/media_file_system_registry.h"
 
 #include <set>
 
@@ skipping 122 matching lines @@
                     content::Source<RenderProcessHost>(rph));
 }
 
 std::string MediaFileSystemRegistry::RegisterPathAsFileSystem(
     const FilePath& path) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   // Sanity checks for |path|.
   CHECK(path.IsAbsolute());
   CHECK(!path.ReferencesParent());
-  // Make sure |path| does not refer to '/' on Unix.
-  // TODO(thestig) Check how BaseName() works for say, 'C:\' on Windows.
-  CHECK(!path.BaseName().IsAbsolute());
-  CHECK(!path.BaseName().empty());
 
-  std::set<FilePath> fileset;
-  fileset.insert(path);
+  std::string name = IsolatedContext::GetNameForPath(path);
   const std::string fsid =
-      IsolatedContext::GetInstance()->RegisterIsolatedFileSystem(fileset);
+      IsolatedContext::GetInstance()->RegisterFileSystemForFile(name, path);
   CHECK(!fsid.empty());
   return fsid;
 }
 
 void MediaFileSystemRegistry::RevokeMediaFileSystem(const FilePath& path) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   IsolatedContext* isolated_context = IsolatedContext::GetInstance();
   for (ChildIdToMediaFSMap::iterator child_it = media_fs_map_.begin();
        child_it != media_fs_map_.end();
        ++child_it) {
     MediaPathToFSIDMap& child_map = child_it->second;
     MediaPathToFSIDMap::iterator media_path_it = child_map.find(path);
     if (media_path_it == child_map.end())
       continue;
-    isolated_context->RevokeIsolatedFileSystem(media_path_it->second);
+    isolated_context->RevokeFileSystem(media_path_it->second);
     child_map.erase(media_path_it);
   }
 }
 
 }  // namespace chrome