Remove FileSystem runtime flag for blink

Source/modules/filesystem/DevToolsHostFileSystem.idl

Index: Source/modules/filesystem/DevToolsHostFileSystem.idl
diff --git a/Source/modules/filesystem/DevToolsHostFileSystem.idl b/Source/modules/filesystem/DevToolsHostFileSystem.idl
index c0a283af70711f3f5ac9307701565e3d895f3e29..59c9268f5e07da8ba0e79f71e6f7357f248c9048 100644
--- a/Source/modules/filesystem/DevToolsHostFileSystem.idl
+++ b/Source/modules/filesystem/DevToolsHostFileSystem.idl
@@ -2,9 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-[
-    RuntimeEnabled=FileSystem,
-] partial interface DevToolsHost {
+partial interface DevToolsHost {
     DOMFileSystem isolatedFileSystem(DOMString fileSystemId, DOMString registeredName);
     void upgradeDraggedFileSystemPermissions(DOMFileSystem domFileSystem);
 };