Make sure FrameScheduler is cleared when LocalFrame::detach() finishes

components/scheduler/base/task_queue_impl.h

 // Copyright 2015 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 CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_IMPL_H_
 #define CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_IMPL_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 187 matching lines @@
     TaskQueueManager* task_queue_manager;
     PumpPolicy pump_policy;
     TimeDomain* time_domain;
 
     std::unique_ptr<WorkQueue> delayed_work_queue;
     std::unique_ptr<WorkQueue> immediate_work_queue;
     std::priority_queue<Task> delayed_incoming_queue;
     base::ObserverList<base::MessageLoop::TaskObserver> task_observers;
     size_t set_index;
     bool is_enabled;
-    base::trace_event::BlameContext* blame_context;  // Not owned.
+    base::WeakPtr<base::trace_event::BlameContext> blame_context;
   };
 
   ~TaskQueueImpl() override;
 
   bool PostImmediateTaskImpl(const tracked_objects::Location& from_here,
                              const base::Closure& task,
                              TaskType task_type);
   bool PostDelayedTaskImpl(const tracked_objects::Location& from_here,
                            const base::Closure& task,
                            base::TimeDelta delay,
@@ skipping 81 matching lines @@
   const bool should_notify_observers_;
   const bool should_report_when_execution_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueImpl);
 };
 
 }  // namespace internal
 }  // namespace scheduler
 
 #endif  // CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_IMPL_H_