Support Sync following Gaia OAuth authentication

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 8c69cd9752383930ffa89a707a8ef2a79f31a849..1d22a53673c65fc12e5ee2f9df2c29b384be5783 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1280,6 +1280,9 @@ const char kAcknowledgedSyncTypes[] = "sync.acknowledged_types";
 // startup so that the user doesn't need to provide credentials on each start.
 const char kEncryptionBootstrapToken[] = "sync.encryption_bootstrap_token";
 
+// Boolean tracking whether the user authenticated with OAuth.
+const char kSyncUsingOAuth[] = "sync.using_oauth";
+
 // Boolean tracking whether the user chose to specify a secondary encryption
 // passphrase.
 const char kSyncUsingSecondaryPassphrase[] = "sync.using_secondary_passphrase";