Use SNAPSHOT sync mode for LocalSync

chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc

Index: chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
diff --git a/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc b/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
index 583bfe86c46dd8d5278d714a1def3e739605ad68..82bcb7f7c7732a663c9cf980acebb2cf8c7e03f9 100644
--- a/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
+++ b/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/sync_file_system/syncable_file_system_util.h"
 
+#include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ -115,16 +116,20 @@ TEST(SyncableFileSystemUtilTest, SerializeBeforeOpenFileSystem) {
   ScopedEnableSyncFSDirectoryOperation enable_directory_operation_;
   const std::string serialized = kSyncableFileSystemRootURI +
       CreateNormalizedFilePath(kPath).AsUTF8Unsafe();
+  base::ScopedTempDir dir;
   FileSystemURL deserialized;
   base::MessageLoop message_loop;
 
+  ASSERT_TRUE(dir.CreateUniqueTempDir());
+
   // Setting up a full syncable filesystem environment.
   CannedSyncableFileSystem file_system(GURL(kOrigin),
                                        base::MessageLoopProxy::current().get(),
                                        base::MessageLoopProxy::current().get());
   file_system.SetUp();
   scoped_refptr<LocalFileSyncContext> sync_context =
-      new LocalFileSyncContext(base::MessageLoopProxy::current().get(),
+      new LocalFileSyncContext(dir.path(),
+                               base::MessageLoopProxy::current().get(),
                                base::MessageLoopProxy::current().get());
 
   // Before calling initialization we would not be able to get a valid