Pref service: add support for tracked prefs.

services/preferences/persistent_pref_store_impl.cc

 // Copyright 2017 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.
 
 #include "services/preferences/persistent_pref_store_impl.h"
 
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/memory/ptr_util.h"
@@ skipping 56 matching lines @@
 
   // If true then a write is in progress and any update notifications should be
   // ignored, as those updates would originate from ourselves.
   bool write_in_progress_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(Connection);
 };
 
 PersistentPrefStoreImpl::PersistentPrefStoreImpl(
     scoped_refptr<PersistentPrefStore> backing_pref_store,
-    mojom::TrackedPreferenceValidationDelegatePtr validation_delegate,
     base::OnceClosure on_initialized)
-    : backing_pref_store_(backing_pref_store),
-      validation_delegate_(std::move(validation_delegate)) {
+    : backing_pref_store_(backing_pref_store) {
   backing_pref_store_->AddObserver(this);
   if (!backing_pref_store_->IsInitializationComplete()) {
     on_initialized_ = std::move(on_initialized);
     initializing_ = true;
     backing_pref_store_->ReadPrefsAsync(nullptr);
   }
 }
 
 PersistentPrefStoreImpl::~PersistentPrefStoreImpl() {
   backing_pref_store_->RemoveObserver(this);
@@ skipping 62 matching lines @@
 
 void PersistentPrefStoreImpl::ClearMutableValues() {
   backing_pref_store_->ClearMutableValues();
 }
 
 void PersistentPrefStoreImpl::OnConnectionError(Connection* connection) {
   connections_.erase(connection);
 }
 
 }  // namespace prefs