Ensure Origin Thread Affinity for BlameContext

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"
 #include "base/macros.h"
+#include "base/threading/thread_checker.h"
 #include "base/trace_event/trace_log.h"
 
 namespace base {
 namespace trace_event {
 class TracedValue;
 }
 
 namespace trace_event {
 
 // A blame context represents a logical unit to which we want to attribute
@@ skipping 74 matching lines @@
 
   // trace_event::TraceLog::EnabledStateObserver implementation:
   void OnTraceLogEnabled() override;
   void OnTraceLogDisabled() override;
 
  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);

[Sami, 2016/04/26 12:57:12]

Could you add a note here saying that this is always called on the thread on
which this object was created on?

[Xiaocheng, 2016/04/27 12:21:10]

A note on thread safety is added before the class definition.

 
  private:
   bool WasInitialized() const;
 
   // The following string pointers have application lifetime.
   const char* category_;
   const char* name_;
   const char* type_;
   const char* scope_;
   const int64_t id_;
 
   const char* parent_scope_;
   const int64_t parent_id_;
 
   const unsigned char* category_group_enabled_;
 
+  ThreadChecker thread_checker_;
+  scoped_refptr<SingleThreadTaskRunner> task_runner_;
+  WeakPtrFactory<BlameContext> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(BlameContext);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_BLAME_CONTEXT_H_