Change platform app api getDisplayPath to take FileEntry.

chrome/renderer/resources/extensions/file_system_custom_bindings.js

Index: chrome/renderer/resources/extensions/file_system_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/file_system_custom_bindings.js b/chrome/renderer/resources/extensions/file_system_custom_bindings.js
new file mode 100644
index 0000000000000000000000000000000000000000..0e6da3a4f51c397791a632c9ee81b5d989495dfb
--- /dev/null
+++ b/chrome/renderer/resources/extensions/file_system_custom_bindings.js
@@ -0,0 +1,16 @@
+// 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.
+
+// Custom bindings for the fileSystem API.
+
+var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
+
+chromeHidden.registerCustomHook('fileSystem', function(bindingsAPI) {
+  bindingsAPI.apiFunctions.setUpdateArgumentsPostValidate(
+      'getDisplayPath', function(fileEntry, callback) {
+    var fileSystemName = fileEntry.filesystem.name;
+    var relativePath = fileEntry.fullPath.slice(1);
+    return [fileSystemName, relativePath, callback];
+  });
+});