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

sync/syncable/syncable_mock.cc

Index: sync/syncable/syncable_mock.cc
diff --git a/sync/syncable/syncable_mock.cc b/sync/syncable/syncable_mock.cc
index 950f14e0123f206089b487cdec30a5d0ce4633a9..9a57e15d727f760531f5d862b180750d2bba3a8b 100644
--- a/sync/syncable/syncable_mock.cc
+++ b/sync/syncable/syncable_mock.cc
@@ -9,6 +9,9 @@
 
 #include "sync/test/null_transaction_observer.h"
 
+namespace syncer {
+namespace syncable {
+
 MockDirectory::MockDirectory(syncer::UnrecoverableErrorHandler* handler)
     : Directory(&encryptor_, handler, NULL,
                 new syncable::InMemoryDirectoryBackingStore("store")) {
@@ -21,3 +24,6 @@ MockSyncableWriteTransaction::MockSyncableWriteTransaction(
     const tracked_objects::Location& from_here, Directory *directory)
     : WriteTransaction(from_here, syncable::UNITTEST, directory) {
 }
+
+}  // namespace syncable
+}  // namespace syncer