Use of base::StringPairs appropriately in nacl.

components/nacl/renderer/ppb_nacl_private_impl.cc

Index: components/nacl/renderer/ppb_nacl_private_impl.cc
diff --git a/components/nacl/renderer/ppb_nacl_private_impl.cc b/components/nacl/renderer/ppb_nacl_private_impl.cc
index 2f3cd586f6cc490224ab63b751a0c1d4acd00bf5..8ce2a8899a0573ab8513289f8b900688d46071d2 100644
--- a/components/nacl/renderer/ppb_nacl_private_impl.cc
+++ b/components/nacl/renderer/ppb_nacl_private_impl.cc
@@ -420,8 +420,7 @@ void LaunchSelLdr(PP_Instance instance,
   IPC::PlatformFileForTransit nexe_for_transit =
       IPC::InvalidPlatformFileForTransit();
 
-  std::vector<std::pair<
-    std::string /*key*/, std::string /*url*/> > resource_files_to_prefetch;
+  base::StringPairs resource_files_to_prefetch;
   if (process_type == kNativeNaClProcessType && uses_nonsfi_mode) {
     JsonManifest* manifest = GetJsonManifest(instance);
     if (manifest)