Cleanup: Better constify some strings in chrome/browser/{chromeos,extensions}.

chrome/browser/extensions/chrome_app_sorting.cc

Index: chrome/browser/extensions/chrome_app_sorting.cc
diff --git a/chrome/browser/extensions/chrome_app_sorting.cc b/chrome/browser/extensions/chrome_app_sorting.cc
index 13bbc33c7d2e2c91fcbedad60df280bea3e1f4aa..5f05f47696b6cde21032152affaaf8571da231ec 100644
--- a/chrome/browser/extensions/chrome_app_sorting.cc
+++ b/chrome/browser/extensions/chrome_app_sorting.cc
@@ -549,7 +549,7 @@ void ChromeAppSorting::CreateDefaultOrdinals() {
   std::vector<std::string> app_ids;
   chromeos::default_app_order::Get(&app_ids);
 #else
-  const char* kDefaultAppOrder[] = {
+  const char* const kDefaultAppOrder[] = {
     extension_misc::kChromeAppId,
     extensions::kWebStoreAppId,
   };