Delay bookmarks load while the profile is loading.

This CL adds a new DeferredSequencedtaskRunner that queues up tasks
until a first call to Start is issued. It creates such a task runner for the 
execution of bookmarks I/O operations. At profile creation, the bookmarks
task runner is stopped and its execution is started after the profile has
finished loading.

BUG=NONE

Review URL: https://chromiumcodereview.appspot.com/12952005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194956 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 45 insertions, 0 deletions

diff --git a/chrome/browser/profiles/startup_task_runner_service.h b/chrome/browser/profiles/startup_task_runner_service.h
new file mode 100644
index 0000000..f6298a3
--- /dev/null
+++ b/chrome/browser/profiles/startup_task_runner_service.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2013 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.
+
+#ifndef CHROME_BROWSER_PROFILES_STARTUP_TASK_RUNNER_SERVICE_H_
+#define CHROME_BROWSER_PROFILES_STARTUP_TASK_RUNNER_SERVICE_H_
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/threading/non_thread_safe.h"
+#include "chrome/browser/profiles/profile_keyed_service.h"
+
+class Profile;
+
+namespace base {
+class DeferredSequencedTaskRunner;
+}  // namespace base
+
+// This service manages the startup task runners.
+class StartupTaskRunnerService : public base::NonThreadSafe,
+                                 public ProfileKeyedService {
+ public:
+  explicit StartupTaskRunnerService(Profile* profile);
+  virtual ~StartupTaskRunnerService();
+
+  // Returns sequenced task runner where all bookmarks I/O operations are
+  // performed.
+  // This method should only be called from the UI thread.
+  // Note: Using a separate task runner per profile service gives a better
+  // management of the sequence in which the task are started in order to avoid
+  // congestion during start-up (e.g the caller may decide to start loading the
+  // bookmarks only after the history finished).
+  scoped_refptr<base::DeferredSequencedTaskRunner> GetBookmarkTaskRunner();
+
+  // Starts the task runners that are deferred during start-up.
+  void StartDeferredTaskRunners();
+
+ private:
+  Profile* profile_;
+  scoped_refptr<base::DeferredSequencedTaskRunner> bookmark_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(StartupTaskRunnerService);
+};
+
+#endif  // CHROME_BROWSER_PROFILES_STARTUP_TASK_RUNNER_SERVICE_H_