Maintaing the proper order of initialization WeakPtrFactory

base/task/cancelable_task_tracker.cc

 // Copyright 2014 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 "base/task/cancelable_task_tracker.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 42 matching lines @@
 }
 
 }  // namespace
 
 namespace base {
 
 // static
 const CancelableTaskTracker::TaskId CancelableTaskTracker::kBadTaskId = 0;
 
 CancelableTaskTracker::CancelableTaskTracker()
-    : weak_factory_(this), next_id_(1) {}
+    : next_id_(1),weak_factory_(this) {}
 
 CancelableTaskTracker::~CancelableTaskTracker() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   TryCancelAll();
 }
 
 CancelableTaskTracker::TaskId CancelableTaskTracker::PostTask(
     TaskRunner* task_runner,
     const tracked_objects::Location& from_here,
@@ skipping 104 matching lines @@
   DCHECK(success);
 }
 
 void CancelableTaskTracker::Untrack(TaskId id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   size_t num = task_flags_.erase(id);
   DCHECK_EQ(1u, num);
 }
 
 }  // namespace base