scheduler: Add support for tracing scheduler state

content/renderer/scheduler/renderer_scheduler_impl.h

 // 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.
 
 #ifndef CONTENT_RENDERER_SCHEDULER_RENDERER_SCHEDULER_IMPL_H_
 #define CONTENT_RENDERER_SCHEDULER_RENDERER_SCHEDULER_IMPL_H_
 
 #include "base/atomicops.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "content/renderer/scheduler/renderer_scheduler.h"
 #include "content/renderer/scheduler/single_thread_idle_task_runner.h"
 #include "content/renderer/scheduler/task_queue_manager.h"
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace content {
 
 class RendererTaskQueueSelector;
 
 class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
  public:
   RendererSchedulerImpl(
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner);
   ~RendererSchedulerImpl() override;
 
@@ skipping 42 matching lines @@
     bool IsSet() const;
 
    private:
     base::subtle::Atomic32 flag_;
     base::Lock* write_lock_;  // Not owned.
     base::ThreadChecker thread_checker_;
 
     DISALLOW_COPY_AND_ASSIGN(PollableNeedsUpdateFlag);
   };
 
+  // Returns the serialized scheduler state for tracing.
+  scoped_refptr<base::debug::ConvertableToTraceFormat> AsValueLocked(
+      base::TimeTicks optional_now) const;
+  static const char* TaskQueueIdToString(QueueId queue_id);
+  static const char* PolicyToString(Policy policy);
+
   // The time we should stay in CompositorPriority mode for after a touch event.
   static const int kCompositorPriorityAfterTouchMillis = 100;
 
   // IdleTaskDeadlineSupplier Implementation:
   void CurrentIdleTaskDeadlineCallback(base::TimeTicks* deadline_out) const;
 
   // Returns the current scheduler policy. Must be called from the main thread.
   Policy SchedulerPolicy() const;
 
   // Posts a call to UpdatePolicy on the control runner to be run after |delay|
@@ skipping 37 matching lines @@
 
   base::WeakPtr<RendererSchedulerImpl> weak_renderer_scheduler_ptr_;
   base::WeakPtrFactory<RendererSchedulerImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererSchedulerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_SCHEDULER_RENDERER_SCHEDULER_IMPL_H_