Files.app: Add private API to check if PiexLoader is enabled or not.

chrome/browser/chromeos/extensions/file_manager/private_api_misc.cc

 // Copyright 2013 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 "chrome/browser/chromeos/extensions/file_manager/private_api_misc.h"
 
 #include "ash/frame/frame_util.h"
 #include "base/files/file_path.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/stringprintf.h"
@@ skipping 442 matching lines @@
 
   return true;
 }
 
 void FileManagerPrivateGetMimeTypeFunction::OnGetMimeType(
     const std::string& mimeType) {
   SetResult(new base::StringValue(mimeType));
   SendResponse(true);
 }
 
+bool FileManagerPrivateIsPiexLoaderEnabledFunction::RunSync() {
+#if defined(OFFICIAL_BUILD)
+  SetResult(new base::FundamentalValue(true));
+#else
+  SetResult(new base::FundamentalValue(false));
+#endif
+  return true;
+}
+
 }  // namespace extensions