Convert app_launch_index and page_index from int to StringOrdinal.

chrome/browser/extensions/crx_installer.h

Index: chrome/browser/extensions/crx_installer.h
diff --git a/chrome/browser/extensions/crx_installer.h b/chrome/browser/extensions/crx_installer.h
index 23ea41a5599b6a6de0f9cf308c1e351411f49510..f27f211bd7b6b6530714a53ef6f550591b4396c2 100644
--- a/chrome/browser/extensions/crx_installer.h
+++ b/chrome/browser/extensions/crx_installer.h
@@ -154,7 +154,7 @@ class CrxInstaller
     install_cause_ = install_cause;
   }
 
-  void set_page_index(int page_index) {
+  void set_page_index(std::string page_index) {
     page_index_ = page_index;
   }
 
@@ -245,7 +245,7 @@ class CrxInstaller
   scoped_refptr<const Extension> extension_;
 
   // The index of the NTP apps page |extension_| will be shown on.
-  int page_index_;
+  std::string page_index_;
 
   // A parsed copy of the unmodified original manifest, before any
   // transformations like localization have taken place.