content: Add heartbeat trace for CategorizedWorkerPool.

content/renderer/categorized_worker_pool.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 CONTENT_RENDERER_CATEGORIZED_WORKER_POOL_H_
 #define CONTENT_RENDERER_CATEGORIZED_WORKER_POOL_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 98 matching lines @@
   void RunTaskInCategoryWithLockAcquired(cc::TaskCategory category);
 
   // Helper function which signals worker threads if tasks are ready to run.
   void SignalHasReadyToRunTasksWithLockAcquired();
 
   // Determines if we should run a new task for the given category. This factors
   // in whether a task is available and whether the count of running tasks is
   // low enough to start a new one.
   bool ShouldRunTaskForCategoryWithLockAcquired(cc::TaskCategory category);
 
+  // Wait for more tasks to run on the given thread.
+  void WaitForMoreTasksWithLockAcquired(
+      base::ConditionVariable* has_ready_to_run_tasks_cv);
+
   // The actual threads where work is done.
   std::vector<std::unique_ptr<base::SimpleThread>> threads_;
 
   // Lock to exclusively access all the following members that are used to
   // implement the TaskRunner and TaskGraphRunner interfaces.
   base::Lock lock_;
   // Stores the tasks to be run, sorted by priority.
   cc::TaskGraphWorkQueue work_queue_;
   // Namespace used to schedule tasks in the task graph runner.
   cc::NamespaceToken namespace_token_;
@@ skipping 10 matching lines @@
   // Condition variable that is waited on by origin threads until a namespace
   // has finished running all associated tasks.
   base::ConditionVariable has_namespaces_with_finished_running_tasks_cv_;
   // Set during shutdown. Tells Run() to return when no more tasks are pending.
   bool shutdown_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_CATEGORIZED_WORKER_POOL_H_