Make Isolated file system writable only if it is configured so

webkit/fileapi/isolated_file_util.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 "webkit/fileapi/isolated_file_util.h"
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 301 matching lines @@
     return true;
   }
   return NativeFileUtil::DirectoryExists(platform_path);
 }
 
 bool IsolatedFileUtil::IsDirectoryEmpty(
     FileSystemOperationContext* context,
     const FileSystemPath& path) {
   std::string filesystem_id;
   FilePath platform_path;
-  if (!GetPlatformPath(path, &platform_path))
+  if (!IsolatedContext::GetInstance()->CrackIsolatedPath(
+          path.internal_path(), &filesystem_id,
+          NULL, &platform_path))
     return false;
   if (platform_path.empty()) {
     // The root directory case.
     std::vector<FilePath> toplevels;
     bool success = IsolatedContext::GetInstance()->GetTopLevelPaths(
         filesystem_id, &toplevels);
     DCHECK(success);
     return toplevels.empty();
   }
   return NativeFileUtil::IsDirectoryEmpty(platform_path);
@@ skipping 32 matching lines @@
   std::string filesystem_id;
   FilePath root_path;
   if (!IsolatedContext::GetInstance()->CrackIsolatedPath(
           virtual_path.internal_path(), &filesystem_id,
           &root_path, platform_path))
     return false;
   return true;
 }
 
 }  // namespace