[Sync] Put everything in sync/api into csync namespace

sync/api/sync_error.h

Index: sync/api/sync_error.h
diff --git a/sync/api/sync_error.h b/sync/api/sync_error.h
index 2bdb9eba69a038b3d95ffa163655cb422207f7a4..6cd808aaaad3c29d8811388e6332c87e69d8a211 100644
--- a/sync/api/sync_error.h
+++ b/sync/api/sync_error.h
@@ -16,6 +16,8 @@ namespace tracked_objects {
 class Location;
 }  // namespace tracked_objects
 
+namespace csync {
+
 // Sync errors are used for debug purposes and handled internally and/or
 // exposed through Chrome's "about:sync" internal page. They are considered
 // unrecoverable for the datatype creating them, and should only be used as
@@ -82,4 +84,6 @@ class SyncError {
 // gmock printer helper.
 void PrintTo(const SyncError& sync_error, std::ostream* os);
 
+}  // namespace csync
+
 #endif  // SYNC_API_SYNC_ERROR_H_