Convert app_launch_index and page_index from int to StringOrdinal.

chrome/common/extensions/extension_constants.cc

 // Copyright (c) 2011 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/common/extensions/extension_constants.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/string_util.h"
@@ skipping 480 matching lines @@
 
 // The file to write our decoded message catalogs to, relative to the
 // extension_path.
 const char* kDecodedMessageCatalogsFilename = "DECODED_MESSAGE_CATALOGS";
 }
 
 namespace extension_misc {
 const char* kBookmarkManagerId = "eemcgdkfndhakfknompkggombfjjjeno";
 const char* kWebStoreAppId = "ahfgeienlihckogmohjhadlkjgocpleb";
 const char* kCloudPrintAppId = "mfehgcgbbipciphmccgaenjidiccnmng";
+const char* kUnsetIndex = "-1";
 const char* kAppsPromoHistogram = "Extensions.AppsPromo";
 const char* kAppLaunchHistogram = "Extensions.AppLaunch";
 #if defined(OS_CHROMEOS)
 const char* kAccessExtensionPath =
     "/usr/share/chromeos-assets/accessibility/extensions";
 const char* kChromeVoxDirectoryName = "access_chromevox";
 #endif
 
 }