Plumb Task Scheduler Histograms to the Task Scheduler Internals Page

base/task_scheduler/task_scheduler.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_TASK_SCHEDULER_TASK_SCHEDULER_H_
 #define BASE_TASK_SCHEDULER_TASK_SCHEDULER_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/base_export.h"
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "base/task_runner.h"
 #include "base/task_scheduler/task_traits.h"
 
 namespace tracked_objects {
 class Location;
 }
 
 namespace base {
 
+class HistogramBase;
 class SchedulerWorkerPoolParams;
 
 // Interface for a task scheduler and static methods to manage the instance used
 // by the post_task.h API. Note: all base/task_scheduler users should go through
 // post_task.h instead of TaskScheduler except for the one callsite per process
 // which manages the process' instance.
 class BASE_EXPORT TaskScheduler {
  public:
   // Returns the index of the worker pool in which a task with |traits| should
   // run. This should be coded in a future-proof way: new traits should
   // gracefully map to a default pool.
   using WorkerPoolIndexForTraitsCallback =
       Callback<size_t(const TaskTraits& traits)>;
 
   virtual ~TaskScheduler() = default;
 
   // Posts |task| with specific |traits|.
   // For one off tasks that don't require a TaskRunner.
   virtual void PostTaskWithTraits(const tracked_objects::Location& from_here,
                                   const TaskTraits& traits,
                                   const Closure& task) = 0;
 
   // Returns a TaskRunner whose PostTask invocations will result in scheduling
   // Tasks with |traits| which will be executed according to |execution_mode|.
   virtual scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
       const TaskTraits& traits,
       ExecutionMode execution_mode) = 0;
 
+  // Returns a vector of all histograms available in this task scheduler.
+  virtual std::vector<const HistogramBase*> GetHistograms() const = 0;
+
   // Synchronously shuts down the scheduler. Once this is called, only tasks
   // posted with the BLOCK_SHUTDOWN behavior will be run. When this returns:
   // - All SKIP_ON_SHUTDOWN tasks that were already running have completed their
   //   execution.
   // - All posted BLOCK_SHUTDOWN tasks have completed their execution.
   // - CONTINUE_ON_SHUTDOWN tasks might still be running.
   // Note that an implementation can keep threads and other resources alive to
   // support running CONTINUE_ON_SHUTDOWN after this returns. This can only be
   // called once.
   virtual void Shutdown() = 0;
@@ skipping 28 matching lines @@
 
   // Retrieve the TaskScheduler set via CreateAndSetDefaultTaskScheduler() or
   // SetInstance(). This should be used very rarely; most users of TaskScheduler
   // should use the post_task.h API.
   static TaskScheduler* GetInstance();
 };
 
 }  // namespace base
 
 #endif  // BASE_TASK_SCHEDULER_TASK_SCHEDULER_H_