[USS] Implement ApplySyncChanges and OnURLVisited/Modified/Deleted.

components/sync/model/recording_model_type_change_processor.h

Index: components/sync/model/recording_model_type_change_processor.h
diff --git a/components/sync/model/recording_model_type_change_processor.h b/components/sync/model/recording_model_type_change_processor.h
index 861ec23207b4bf656dab7c4df23b2f5179d6405a..a749277d749a03711aad5aaf033ce5d8d75f6e5f 100644
--- a/components/sync/model/recording_model_type_change_processor.h
+++ b/components/sync/model/recording_model_type_change_processor.h
@@ -28,6 +28,10 @@ class RecordingModelTypeChangeProcessor : public FakeModelTypeChangeProcessor {
            MetadataChangeList* metadata_changes) override;
   void Delete(const std::string& storage_key,
               MetadataChangeList* metadata_changes) override;
+  void UpdateStorageKey(const EntityData& entity_data,
+                        const std::string& storage_key,
+                        MetadataChangeList* metadata_change_list) override;
+  void UntrackEntity(const EntityData& entity_data) override;
   void ModelReadyToSync(std::unique_ptr<MetadataBatch> batch) override;
   bool IsTrackingMetadata() override;
 
@@ -38,8 +42,17 @@ class RecordingModelTypeChangeProcessor : public FakeModelTypeChangeProcessor {
     return put_multimap_;
   }
 
+  const std::multimap<std::string, std::unique_ptr<EntityData>>&
+  update_multimap() const {
+    return update_multimap_;
+  }
+
   const std::set<std::string>& delete_set() const { return delete_set_; }
 
+  const std::set<std::unique_ptr<EntityData>>& untrack_set() const {
+    return untrack_set_;
+  }
+
   MetadataBatch* metadata() const { return metadata_.get(); }
 
   // Returns a callback that constructs a processor and assigns a raw pointer to
@@ -53,7 +66,9 @@ class RecordingModelTypeChangeProcessor : public FakeModelTypeChangeProcessor {
 
  private:
   std::multimap<std::string, std::unique_ptr<EntityData>> put_multimap_;
+  std::multimap<std::string, std::unique_ptr<EntityData>> update_multimap_;
   std::set<std::string> delete_set_;
+  std::set<std::unique_ptr<EntityData>> untrack_set_;
   std::unique_ptr<MetadataBatch> metadata_;
   bool is_tracking_metadata_ = true;
 };