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

base/trace_event/blame_context.h

 // Copyright 2016 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_TRACE_EVENT_BLAME_CONTEXT_H_
 #define BASE_TRACE_EVENT_BLAME_CONTEXT_H_
 
 #include <inttypes.h>
 
 #include "base/base_export.h"
@@ skipping 86 matching lines @@
   const char* category() const { return category_; }
   const char* name() const { return name_; }
   const char* type() const { return type_; }
   const char* scope() const { return scope_; }
   int64_t id() const { return id_; }
 
   // trace_event::TraceLog::EnabledStateObserver implementation:
   void OnTraceLogEnabled() override;
   void OnTraceLogDisabled() override;
 
+  // Returns a WeakPtr of itself.
+  WeakPtr<BlameContext> weak_ptr() { return weak_factory_.GetWeakPtr(); }
+
  protected:
   // Serialize the properties of this blame context into |state|. Subclasses can
   // override this method to record additional properties (e.g, the URL for an
   // <iframe> blame context). Note that an overridden implementation must still
   // call this base method.
   virtual void AsValueInto(trace_event::TracedValue* state);
 
  private:
   bool WasInitialized() const;
 
@@ skipping 12 matching lines @@
   ThreadChecker thread_checker_;
   WeakPtrFactory<BlameContext> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BlameContext);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_BLAME_CONTEXT_H_