Implement frame attribution (FrameBlamer)

components/scheduler/child/single_thread_idle_task_runner.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 "components/scheduler/child/single_thread_idle_task_runner.h"
 
 #include "base/location.h"
+#include "base/trace_event/blame_context.h"
 #include "base/trace_event/trace_event.h"
 
 namespace scheduler {
 
 SingleThreadIdleTaskRunner::SingleThreadIdleTaskRunner(
     scoped_refptr<base::SingleThreadTaskRunner> idle_priority_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> after_wakeup_task_runner,
     Delegate* delegate,
     const char* tracing_category)
     : idle_priority_task_runner_(idle_priority_task_runner),
       after_wakeup_task_runner_(after_wakeup_task_runner),
       delegate_(delegate),
       tracing_category_(tracing_category),
+      blame_context_(nullptr),
       weak_factory_(this) {
   DCHECK(!idle_priority_task_runner_ ||
          idle_priority_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!after_wakeup_task_runner_ ||
          after_wakeup_task_runner_->RunsTasksOnCurrentThread());
   weak_scheduler_ptr_ = weak_factory_.GetWeakPtr();
 }
 
 SingleThreadIdleTaskRunner::~SingleThreadIdleTaskRunner() {
 }
@@ skipping 34 matching lines @@
   after_wakeup_task_runner_->PostTask(
       FROM_HERE, base::Bind(&SingleThreadIdleTaskRunner::PostIdleTask,
                             weak_scheduler_ptr_, from_here, idle_task));
 }
 
 void SingleThreadIdleTaskRunner::RunTask(IdleTask idle_task) {
   base::TimeTicks deadline = delegate_->WillProcessIdleTask();
   TRACE_EVENT1(tracing_category_, "SingleThreadIdleTaskRunner::RunTask",
                "allotted_time_ms",
                (deadline - base::TimeTicks::Now()).InMillisecondsF());
+  if (blame_context_)
+    blame_context_->Enter();
   idle_task.Run(deadline);
+  if (blame_context_)
+    blame_context_->Leave();
   delegate_->DidProcessIdleTask();
 }
 
+void SingleThreadIdleTaskRunner::SetBlameContext(
+    base::trace_event::BlameContext* blame_context) {
+  blame_context_ = blame_context;
+}
+
 }  // namespace scheduler