storage::IsolatedContext API changed

https://chromium-review.googlesource.com/c/chromium/src/+/1603486

atom/browser/common_web_contents_delegate.cc

@@ -84,22 +84,23 @@ std::string RegisterFileSystem(content::WebContents* web_contents,
                                const base::FilePath& path) {
   auto* isolated_context = storage::IsolatedContext::GetInstance();
   std::string root_name(kRootName);
-  std::string file_system_id = isolated_context->RegisterFileSystemForPath(
-      storage::kFileSystemTypeNativeLocal, std::string(), path, &root_name);
+  storage::IsolatedContext::ScopedFSHandle file_system =
+      isolated_context->RegisterFileSystemForPath(
+          storage::kFileSystemTypeNativeLocal, std::string(), path, &root_name);
 
   content::ChildProcessSecurityPolicy* policy =
       content::ChildProcessSecurityPolicy::GetInstance();
   content::RenderViewHost* render_view_host = web_contents->GetRenderViewHost();
   int renderer_id = render_view_host->GetProcess()->GetID();
-  policy->GrantReadFileSystem(renderer_id, file_system_id);
-  policy->GrantWriteFileSystem(renderer_id, file_system_id);
-  policy->GrantCreateFileForFileSystem(renderer_id, file_system_id);
-  policy->GrantDeleteFromFileSystem(renderer_id, file_system_id);
+  policy->GrantReadFileSystem(renderer_id, file_system.id());
+  policy->GrantWriteFileSystem(renderer_id, file_system.id());
+  policy->GrantCreateFileForFileSystem(renderer_id, file_system.id());
+  policy->GrantDeleteFromFileSystem(renderer_id, file_system.id());
 
   if (!policy->CanReadFile(renderer_id, path))
     policy->GrantReadFile(renderer_id, path);
 
-  return file_system_id;
+  return file_system.id();
 }
 
 FileSystem CreateFileSystemStruct(content::WebContents* web_contents,