Delay bookmarks load while the profile is loading.

base/deferred_sequenced_task_runner.h

Index: base/deferred_sequenced_task_runner.h
diff --git a/base/deferred_sequenced_task_runner.h b/base/deferred_sequenced_task_runner.h
new file mode 100644
index 0000000000000000000000000000000000000000..5fd66bed89fd5c7f4d39342ebb6b7d0a59fd8b3b
--- /dev/null
+++ b/base/deferred_sequenced_task_runner.h
@@ -0,0 +1,83 @@
+// 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 BASE_DEFERRED_SEQUENCED_TASKRUNNER_H_
+#define BASE_DEFERRED_SEQUENCED_TASKRUNNER_H_
+
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/sequenced_task_runner.h"
+#include "base/time.h"
+#include "base/tracked_objects.h"
+
+namespace base {
+
+// A DeferredSequencedTaskRunner is a subclass of SequencedTaskRunner that
+// queues up all requests until the first call to Start() is issued.
+class BASE_EXPORT DeferredSequencedTaskRunner : public SequencedTaskRunner {
+ public:
+  explicit DeferredSequencedTaskRunner(
+      const scoped_refptr<SequencedTaskRunner>& target_runner);
+
+  // TaskRunner implementation
+  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
+                               const Closure& task,
+                               TimeDelta delay) OVERRIDE;

[erikwright (departed), 2013/04/15 17:56:25]

compiler_specific.h for OVERRIDE

[msarda, 2013/04/17 09:53:55]

Done.

+

[erikwright (departed), 2013/04/15 17:56:25]

remove this blank line

[msarda, 2013/04/17 09:53:55]

Done.

+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
+
+  // SequencedTaskRunner implementation
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& from_here,
+      const Closure& task,
+      TimeDelta delay) OVERRIDE;
+
+  // Start the execution - posts all tasks in the |deferred_tasks_queue_| to

[erikwright (departed), 2013/04/15 17:56:25]

"posts all queued tasks to the target executor." rather than referring to
internal implementation details.

[msarda, 2013/04/17 09:53:55]

The comment on what delay means was added following jyasskin's review.

[erikwright (departed), 2013/04/17 14:41:19]

Sorry, the only change I'm referring to is s/tasks in the
|deferred_tasks_queue_|/queued tasks/

i.e., don't refer to deferred_tasks_queue_ in the public documentation (this is
an implementation detail).

I agree that the delay behaviour is an important part of the API.

[msarda, 2013/04/17 15:29:10]

Done.

+  // the target executor. The deferred tasks are posted with their initial
+  // delay, meaning that the task execution delay is actually measured from
+  // Start.
+  // Fails when called a second time.

[erikwright (departed), 2013/04/15 17:56:25]

Ignores second and further calls. ?

[msarda, 2013/04/17 09:53:55]

That was the initial implementation. I changed it to fail on subsequent calls
after willchan's review.

+  void Start();
+
+ private:
+  struct DeferredTask  {
+    DeferredTask();
+    ~DeferredTask();

[erikwright (departed), 2013/04/15 17:56:25]

blank line after destructor?

[msarda, 2013/04/17 09:53:55]

Done.

+    tracked_objects::Location posted_from;
+    Closure task;
+    // The delay this task was initially posted with.
+    TimeDelta delay;
+    bool is_non_nestable;
+  };
+
+  virtual ~DeferredSequencedTaskRunner();
+
+  // Creates a |Task| object and adds it to |deferred_tasks_queue_|.
+  void QueueDeferredTask(const tracked_objects::Location& from_here,
+                         const Closure& task,
+                         TimeDelta delay,
+                         bool is_non_nestable);
+
+  mutable Lock lock_;

[erikwright (departed), 2013/04/15 17:56:25]

Add a comment indicating what members are protected by this lock.

[erikwright (departed), 2013/04/15 17:56:25]

missing an #include for Lock

[msarda, 2013/04/17 09:53:55]

Done.

[msarda, 2013/04/17 09:53:55]

Done.

+
+  // True if this DeferredSequencedTaskRunner has already been started.

[erikwright (departed), 2013/04/15 17:56:25]

I'm mildly opposed to the presence of these member variable comments. I think
they are all self-evident.

[msarda, 2013/04/17 09:53:55]

I removed them.

+  bool started_;
+
+  // Target task runner that executes the tasks.
+  const scoped_refptr<SequencedTaskRunner> target_task_runner_;
+
+  // Queue of tasks to be posted to |target_task_runner_| when this
+  // |DeferredSequencedTaskRunner| is started.
+  std::vector<DeferredTask> deferred_tasks_queue_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeferredSequencedTaskRunner);
+};
+
+}  // namespace base
+
+#endif  // BASE_DEFERRED_SEQUENCED_TASKRUNNER_H_