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 RendererSchedulerSelector;
 
 class RendererSchedulerImpl : public RendererScheduler,
                               private IdleTaskDeadlineSupplier {
  public:
   RendererSchedulerImpl();
   virtual ~RendererSchedulerImpl();
 
@@ skipping 44 matching lines @@
     kControlTaskQueue,
     // Must be the last entry.
     kTaskQueueCount,
   };
 
   enum Policy {
     kNormalPriorityPolicy,
     kCompositorPriorityPolicy,
   };
 
+  // Returns the serialized scheduler state for tracing.
+  scoped_refptr<base::debug::ConvertableToTraceFormat> AsValueLocked() 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;
 
   // Implementation of IdleTaskDeadlineSupplier
   virtual base::TimeTicks CurrentIdleTaskDeadline() const override;
 
   // Returns the current scheduler policy. This may involve updating the
   // current policy if a new signal has arrived. Must be called from the main
   // thread.
   Policy SchedulerPolicy();
@@ skipping 15 matching lines @@
   scoped_refptr<SingleThreadIdleTaskRunner> idle_task_runner_;
 
   // Don't access current_policy_ directly, instead use SchedulerPolicy().
   base::subtle::AtomicWord policy_may_need_update_;
   Policy current_policy_;
 
   base::TimeTicks estimated_next_frame_begin_;
 
   // The incoming_signals_lock_ mutex protects access to last_input_time_
   // and write access to policy_may_need_update_.
-  base::Lock incoming_signals_lock_;
+  mutable base::Lock incoming_signals_lock_;

[alexclarke, 2014/10/27 17:58:11]

Hmm I thought that AssertAcquired was const:

https://code.google.com/p/chromium/codesearch#chromium/src/base/synchronizati...

[Sami, 2014/10/28 12:57:47]

Oops, I added this since I was taking the lock earlier but don't need to do that
anymore => removed.

   base::TimeTicks last_input_time_;
 
   base::WeakPtr<RendererSchedulerImpl> weak_renderer_scheduler_ptr_;
   base::WeakPtrFactory<RendererSchedulerImpl> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_SCHEDULER_RENDERER_SCHEDULER_IMPL_H_