Pref service: Batch pref updates.

services/preferences/public/cpp/pref_store_impl.cc

Index: services/preferences/public/cpp/pref_store_impl.cc
diff --git a/services/preferences/public/cpp/pref_store_impl.cc b/services/preferences/public/cpp/pref_store_impl.cc
index b88e99e3aeba86ba4cb5a465b2672c2782bb3188..c2289621e7e639db648661299ff750a2a5d96d83 100644
--- a/services/preferences/public/cpp/pref_store_impl.cc
+++ b/services/preferences/public/cpp/pref_store_impl.cc
@@ -26,14 +26,18 @@ class PrefStoreImpl::Observer {
     if (!base::ContainsKey(prefs_, key))
       return;
 
-    observer_->OnPrefChanged(key, value.CreateDeepCopy());
+    std::vector<mojom::PrefUpdatePtr> updates;
+    updates.push_back(mojom::PrefUpdate::New(key, value.CreateDeepCopy(), 0));
+    observer_->OnPrefsChanged(std::move(updates));
   }
 
   void OnPrefRemoved(const std::string& key) const {
     if (!base::ContainsKey(prefs_, key))
       return;
 
-    observer_->OnPrefChanged(key, nullptr);
+    std::vector<mojom::PrefUpdatePtr> updates;
+    updates.push_back(mojom::PrefUpdate::New(key, nullptr, 0));
+    observer_->OnPrefsChanged(std::move(updates));
   }
 
  private: