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

components/scheduler/child/single_thread_idle_task_runner.h

 // 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.
 
 #ifndef COMPONENTS_SCHEDULER_CHILD_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
 #define COMPONENTS_SCHEDULER_CHILD_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/macros.h"
@@ skipping 70 matching lines @@
 
  private:
   friend class base::RefCountedThreadSafe<SingleThreadIdleTaskRunner>;
 
   void RunTask(IdleTask idle_task);
 
   scoped_refptr<base::SingleThreadTaskRunner> idle_priority_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> after_wakeup_task_runner_;
   Delegate* delegate_;  // NOT OWNED
   const char* tracing_category_;
-  base::trace_event::BlameContext* blame_context_;  // Not owned.
+  base::WeakPtr<base::trace_event::BlameContext> blame_context_;
   base::WeakPtr<SingleThreadIdleTaskRunner> weak_scheduler_ptr_;
   base::WeakPtrFactory<SingleThreadIdleTaskRunner> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(SingleThreadIdleTaskRunner);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_CHILD_SINGLE_THREAD_IDLE_TASK_RUNNER_H_