sync: Add non-blocking type encryption support

sync/util/cryptographer.h

Index: sync/util/cryptographer.h
diff --git a/sync/util/cryptographer.h b/sync/util/cryptographer.h
index 2dfdedccf6c212ff787919e71f9cf6c3d6924d9f..fc95aea64817754c6128a28052bdea9e424cb7eb 100644
--- a/sync/util/cryptographer.h
+++ b/sync/util/cryptographer.h
@@ -176,6 +176,9 @@ class SYNC_EXPORT Cryptographer {
   // and/or has a different default key.
   bool KeybagIsStale(const sync_pb::EncryptedData& keybag) const;
 
+  // Returns the name of the Nigori key currently used for encryption.
+  std::string GetDefaultKeyName() const;

[stanisc, 2014/07/30 00:30:05]

Consider disambiguating this function from the one below. Both functions get a
Nigori key and both return a string. And their names are very similar.

[rlarocque, 2014/07/30 21:56:01]

Would renaming this function to GetDefaultNigoriKeyName help?

[stanisc, 2014/07/30 22:20:55]

I guess so. Call this one GetDefaultNigoriKeyName and the other one -
GetDefaultNigoriKeyData.

[rlarocque, 2014/07/30 22:28:47]

Done.

+
   // Returns a serialized sync_pb::NigoriKey version of current default
   // encryption key.
   std::string GetDefaultNigoriKey() const;