Add a mojo bridge for PersistentPrefStore.

chrome/browser/profiles/profile_impl.cc

Index: chrome/browser/profiles/profile_impl.cc
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index 2f493aab7d8d2388ee5a28a51334402f60451c0e..fd486d134352b56079cb85319007c8e20214b530 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -480,13 +480,21 @@ ProfileImpl::ProfileImpl(
   if (safe_browsing_service.get()) {
     pref_validation_delegate_ =
         safe_browsing_service->CreatePreferenceValidationDelegate(this);
+    if (pref_validation_delegate_) {
+      pref_validation_delegate_weak_factory_ = base::MakeUnique<
+          base::WeakPtrFactory<TrackedPreferenceValidationDelegate>>(
+          pref_validation_delegate_.get());
+    }
   }
 
   content::BrowserContext::Initialize(this, path_);
 
   {
     prefs_ = chrome_prefs::CreateProfilePrefs(
-        path_, sequenced_task_runner, pref_validation_delegate_.get(),
+        path_, sequenced_task_runner,
+        pref_validation_delegate_weak_factory_
+            ? pref_validation_delegate_weak_factory_->GetWeakPtr()
+            : base::WeakPtr<TrackedPreferenceValidationDelegate>(),
         profile_policy_connector_->policy_service(), supervised_user_settings,
         CreateExtensionPrefStore(this, false), pref_registry_, async_prefs);
     // Register on BrowserContext.