[scheduler] Bunch of improvements for blink scheduler tracing

third_party/WebKit/public/platform/scheduler/base/task_queue.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 THIRD_PARTY_WEBKIT_PUBLIC_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_
 #define THIRD_PARTY_WEBKIT_PUBLIC_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/optional.h"
@@ skipping 36 matching lines @@
     // Queues with normal priority are the default.
     NORMAL_PRIORITY,
     // Queues with best effort priority will only be run if all other queues are
     // empty. They can be starved by the other queues.
     BEST_EFFORT_PRIORITY,
     // Must be the last entry.
     QUEUE_PRIORITY_COUNT,
     FIRST_QUEUE_PRIORITY = CONTROL_PRIORITY,
   };
 
+  // Can be called on any thread.
+  static const char* PriorityToString(QueuePriority priority);
+
   enum class QueueType {
     // Keep TaskQueue::NameForQueueType in sync.
     // This enum is used for a histogram and it should not be re-numbered.
     CONTROL = 0,
     DEFAULT = 1,
     DEFAULT_LOADING = 2,
     DEFAULT_TIMER = 3,
     UNTHROTTLED = 4,
     FRAME_LOADING = 5,
     FRAME_TIMER = 6,
@@ skipping 118 matching lines @@
  protected:
   ~TaskQueue() override {}
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueue);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_PUBLIC_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_