[Sync] Move sync/{internal_api,syncable} into syncer namespace

sync/internal_api/public/base_transaction.h

Index: sync/internal_api/public/base_transaction.h
diff --git a/sync/internal_api/public/base_transaction.h b/sync/internal_api/public/base_transaction.h
index 067239bd416173fcbc8980353c5e04ee13672c1a..09d8a58ae8936e48404d0543894a941c6750efda 100644
--- a/sync/internal_api/public/base_transaction.h
+++ b/sync/internal_api/public/base_transaction.h
@@ -10,13 +10,13 @@
 
 #include "sync/util/cryptographer.h"
 
+namespace syncer {
+
 namespace syncable {
 class BaseTransaction;
 class Directory;
 }
 
-namespace syncer {
-
 // Sync API's BaseTransaction, ReadTransaction, and WriteTransaction allow for
 // batching of several read and/or write operations.  The read and write
 // operations are performed by creating ReadNode and WriteNode instances using