This change loads opencryptoki and uses the TPM for keygen tags.

base/nss_util_internal.h

Index: base/nss_util_internal.h
diff --git a/base/nss_util_internal.h b/base/nss_util_internal.h
index 139740b4ab367935de237a73b561901697fe1e6a..4dbd65ff5dc714b8e46b89cc11bc5e3356e5b23a 100644
--- a/base/nss_util_internal.h
+++ b/base/nss_util_internal.h
@@ -17,6 +17,12 @@ namespace base {
 // reference with PK11_FreeSlot.
 PK11SlotInfo* GetDefaultNSSKeySlot();
 
+// On ChromeOS, returns a reference to the builtin hardware TPM
+// slot. Caller must release reference with PK11_FreeSlot.  If no
+// hardware TPM is present, will return NULL.  On other OSs, This is
+// the same as GetDefaultNSSKeySlot().
+PK11SlotInfo* GetPreferredKeySlot();
+
 }  // namespace base
 
 #endif  // BASE_NSS_UTIL_H_