[Sync] Split DirectoryChangeListener for thread-safety

chrome/browser/sync/syncable/syncable_mock.h

Index: chrome/browser/sync/syncable/syncable_mock.h
diff --git a/chrome/browser/sync/syncable/syncable_mock.h b/chrome/browser/sync/syncable/syncable_mock.h
index e6e09127abfa0f1898a1c94e3e3a9ee381ef9c00..31b51b88143b5f12a49e4cfec8ce70a344979933 100644
--- a/chrome/browser/sync/syncable/syncable_mock.h
+++ b/chrome/browser/sync/syncable/syncable_mock.h
@@ -9,6 +9,7 @@
 #include <string>
 
 #include "chrome/browser/sync/syncable/syncable.h"
+#include "chrome/test/sync/null_directory_change_delegate.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -26,6 +27,9 @@ class MockDirectory : public Directory {
 
   MOCK_METHOD1(GetEntryByClientTag,
                syncable::EntryKernel*(const std::string&));
+
+ private:
+  syncable::NullDirectoryChangeDelegate delegate_;
 };
 
 class MockSyncableWriteTransaction : public syncable::WriteTransaction {