Revert of gpu: GPU service scheduler.

gpu/command_buffer/service/scheduler.h

Index: gpu/command_buffer/service/scheduler.h
diff --git a/gpu/command_buffer/service/scheduler.h b/gpu/command_buffer/service/scheduler.h
deleted file mode 100644
index c6dab1cf58ece563d0f5eb501144ea17b07ae700..0000000000000000000000000000000000000000
--- a/gpu/command_buffer/service/scheduler.h
+++ /dev/null
@@ -1,138 +0,0 @@
-// Copyright (c) 2017 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 GPU_COMMAND_BUFFER_SERVICE_SCHEDULER_H_
-#define GPU_COMMAND_BUFFER_SERVICE_SCHEDULER_H_
-
-#include <queue>
-#include <vector>
-
-#include "base/callback.h"
-#include "base/containers/flat_map.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-#include "base/synchronization/lock.h"
-#include "base/threading/thread_checker.h"
-#include "gpu/command_buffer/common/scheduling_priority.h"
-#include "gpu/command_buffer/common/sync_token.h"
-#include "gpu/command_buffer/service/sequence_id.h"
-#include "gpu/gpu_export.h"
-
-namespace base {
-class SingleThreadTaskRunner;
-namespace trace_event {
-class ConvertableToTraceFormat;
-}
-}
-
-namespace gpu {
-class SyncPointManager;
-
-class GPU_EXPORT Scheduler {
- public:
-  Scheduler(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-            SyncPointManager* sync_point_manager);
-
-  virtual ~Scheduler();
-
-  // Create a sequence with given priority. Returns an identifier for the
-  // sequence that can be used with SyncPonintManager for creating sync point
-  // release clients. Sequences start off as enabled (see |EnableSequence|).
-  SequenceId CreateSequence(SchedulingPriority priority);
-
-  // Destroy the sequence and run any scheduled tasks immediately.
-  void DestroySequence(SequenceId sequence_id);
-
-  // Enables the sequence so that its tasks may be scheduled.
-  void EnableSequence(SequenceId sequence_id);
-
-  // Disables the sequence.
-  void DisableSequence(SequenceId sequence_id);
-
-  // Schedules task (closure) to run on the sequence. The task is blocked until
-  // the sync token fences are released or determined to be invalid. Tasks are
-  // run in the order in which they are submitted.
-  void ScheduleTask(SequenceId sequence_id,
-                    base::OnceClosure closure,
-                    const std::vector<SyncToken>& sync_token_fences);
-
-  // Continue running task on the sequence with the closure. This must be called
-  // while running a previously scheduled task.
-  void ContinueTask(SequenceId sequence_id, base::OnceClosure closure);
-
-  // If the sequence should yield so that a higher priority sequence may run.
-  bool ShouldYield(SequenceId sequence_id);
-
- private:
-  class Sequence;
-
-  struct SchedulingState {
-    static bool Comparator(const SchedulingState& lhs,
-                           const SchedulingState& rhs) {
-      return rhs.RunsBefore(lhs);
-    }
-
-    SchedulingState();
-    SchedulingState(const SchedulingState& other);
-    ~SchedulingState();
-
-    bool RunsBefore(const SchedulingState& other) const {
-      return std::tie(priority, order_num) <
-             std::tie(other.priority, other.order_num);
-    }
-
-    std::unique_ptr<base::trace_event::ConvertableToTraceFormat> AsValue()
-        const;
-
-    SequenceId sequence_id;
-    SchedulingPriority priority = SchedulingPriority::kLowest;
-    uint32_t order_num = 0;
-  };
-
-  void SyncTokenFenceReleased(const SyncToken& sync_token,
-                              uint32_t order_num,
-                              SequenceId release_sequence_id,
-                              SequenceId waiting_sequence_id);
-
-  void TryScheduleSequence(Sequence* sequence);
-
-  void RebuildSchedulingQueue();
-
-  Sequence* GetSequence(SequenceId sequence_id);
-
-  void RunNextTask();
-
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-
-  SyncPointManager* const sync_point_manager_;
-
-  mutable base::Lock lock_;
-
-  // The following are protected by |lock_|.
-  bool running_ = false;
-
-  base::flat_map<SequenceId, std::unique_ptr<Sequence>> sequences_;
-
-  // Used as a priority queue for scheduling sequences. Min heap of
-  // SchedulingState with highest priority (lowest order) in front.
-  std::vector<SchedulingState> scheduling_queue_;
-
-  // If the running sequence should yield so that a higher priority sequence can
-  // run.
-  bool should_yield_ = false;
-
-  // If the scheduling queue needs to be rebuild because a sequence changed
-  // priority.
-  bool rebuild_scheduling_queue_ = false;
-
-  base::ThreadChecker thread_checker_;
-
-  base::WeakPtrFactory<Scheduler> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(Scheduler);
-};
-
-}  // namespace gpu
-
-#endif  // GPU_COMMAND_BUFFER_SERVICE_SCHEDULER_H_