Refactoring, moving and renaming the NetworkActionPredictor.

chrome/browser/predictors/predictor_database_factory.cc

Index: chrome/browser/predictors/predictor_database_factory.cc
diff --git a/chrome/browser/predictors/predictor_database_factory.cc b/chrome/browser/predictors/predictor_database_factory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0afe3db0c758586b7d77c92927d1f0bf2be3b1be
--- /dev/null
+++ b/chrome/browser/predictors/predictor_database_factory.cc
@@ -0,0 +1,43 @@
+// Copyright (c) 2012 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 "chrome/browser/predictors/predictor_database_factory.h"
+
+#include "base/bind.h"
+#include "chrome/browser/predictors/predictor_database.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_dependency_manager.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace predictors {
+
+// static
+PredictorDatabase* PredictorDatabaseFactory::GetForProfile(Profile* profile) {
+  return static_cast<PredictorDatabase*>(
+      GetInstance()->GetBaseForProfile(profile, true));
+}
+
+// static
+PredictorDatabaseFactory* PredictorDatabaseFactory::GetInstance() {
+  return Singleton<PredictorDatabaseFactory>::get();
+}
+
+PredictorDatabaseFactory::PredictorDatabaseFactory()
+    : RefcountedProfileKeyedServiceFactory(
+        "PredictorDatabase", ProfileDependencyManager::GetInstance()) {
+}
+
+PredictorDatabaseFactory::~PredictorDatabaseFactory() {
+}
+
+RefcountedProfileKeyedService*
+    PredictorDatabaseFactory::BuildServiceInstanceFor(
+        Profile* profile) const {
+  PredictorDatabase* db = new PredictorDatabase(profile);
+  content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
+      base::Bind(&PredictorDatabase::Initialize, db));
+  return db;

[willchan no longer on Chromium, 2012/03/13 09:58:39]

I think your bug is here. You create a refcounted object (PredictorDatabase).
Its refcount is 0, and then you post it to the DB thread, which AddRef()s it to
1. There's a race between this variable getting stored into a scoped_refptr
somewhere and Initialize() finishing on the DB thread, leading to a Release() to
refcount 0, and a delete of this object.

[dominich, 2012/03/13 14:55:21]

I agree.

One option is to take what is currently the NetworkActionPredictor and strip it
down to a PredictorDatabaseUI class that is ProfileKeyed and owns a pointer to
the PredictorDatabase. The initialization of the Database is then asynchronous.
Ie, it can do the PostTaskAndReply thing as the current code does and control
access to the PredictorDatabase pointer until initialization is complete.

[Shishir, 2012/03/14 21:14:37]

Changed from a RefcountedProfileKeyedService to ProfileKeyedService along with
other changes to fix this. Asan seems to like the changes now.

+}
+
+}  // namespace predictors