Pref service: Filter updates from read-only pref stores.

services/preferences/public/interfaces/preferences.mojom

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module prefs.mojom;
 
 import "mojo/common/values.mojom";
 import "services/preferences/public/interfaces/preferences_configuration.mojom";
 
 const string kServiceName = "preferences";
@@ skipping 75 matching lines @@
 
   PrefStoreConnection? pref_store_connection;
   PersistentPrefStore? pref_store;
   ReadError read_error;
   bool read_only;
 };
 
 // Manages actual read of preference data. Accepts observers who subscribe to
 // preferences, notifying them of changes.
 interface PrefStore {
-  // Add an observer of changes. This current values of all prefs will not be
-  // communicated through a call to |observer| but instead be returned in
-  // |initial_prefs|.
-  AddObserver() => (PrefStoreConnection connection);
+  // Add an observer of changes to prefs contained in |prefs_to_observe|. This
+  // current values of all prefs will not be communicated through a call to
+  // |observer| but instead be returned in |initial_prefs|.
+  AddObserver(array<string> prefs_to_observe) => (
+      PrefStoreConnection connection);
 };
 
 // Manages a registry of all pref stores. Registered pref stores can be
 // connected to through the |PrefStoreConnector| interface.
 interface PrefStoreRegistry {
   // Register a pref store.
   Register(PrefStoreType type, PrefStore pref_store);
 };
 
 // Allows connections to pref stores registered with |PrefStoreRegistry|.
@@ skipping 31 matching lines @@
   // PrefRegistry::PrefRegistrationFlags and
   // PrefRegistrySyncable::PrefRegistrationFlags.
   uint32 flags;
 };
 
 interface PrefServiceControl {
   // Initializes the pref service. This must be called before the service can
   // be used.
   Init(PersistentPrefStoreConfiguration configuration);
 };