[sync] Implement local data query and migration for bookmarks

This extends helper classes LocalDataQueryHelper and
LocalDataMigrationHelper to support BOOKMARKS.

This CL also builds on the unittests for the two helper classes.

Bug: 1451508
Change-Id: I7381afc5423df518619de901b0a6faab8505682f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4847111
Commit-Queue: Ankush Singh <[email protected]>
Reviewed-by: Marc Treib <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1194055}
diff --git a/components/sync/service/local_data_description.cc b/components/sync/service/local_data_description.cc
index c632c52..43d795f2 100644
--- a/components/sync/service/local_data_description.cc
+++ b/components/sync/service/local_data_description.cc
@@ -42,4 +42,13 @@
   return !(lhs == rhs);
 }
 
+void PrintTo(const LocalDataDescription& desc, std::ostream* os) {
+  *os << "{ type:" << syncer::ModelTypeToDebugString(desc.type)
+      << ", item_count:" << desc.item_count << ", domains:[";
+  for (const auto& domain : desc.domains) {
+    *os << domain << ",";
+  }
+  *os << "], domain_count:" << desc.domain_count;
+}
+
 }  // namespace syncer