Refactored GLContext to own GPUTiming which spawn GPUTimingClients.

gpu/command_buffer/service/gpu_timing.h

-// Copyright (c) 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 GPU_COMMAND_BUFFER_SERVICE_GPU_TIMING_H_
-#define GPU_COMMAND_BUFFER_SERVICE_GPU_TIMING_H_
-
-#include "base/callback.h"
-#include "base/memory/scoped_ptr.h"
-#include "gpu/gpu_export.h"
-
-namespace gfx {
-class GLContext;
-}
-
-namespace gpu {
-class GPUTiming;
-
-// Class to compute the amount of time it takes to fully
-// complete a set of GL commands
-class GPU_EXPORT GPUTimer {
- public:
-  // gpu_timing must outlive GPUTimer instance we're creating.
-  explicit GPUTimer(GPUTiming* gpu_timing);
-  ~GPUTimer();
-
-  void Start();
-  void End();
-  bool IsAvailable();
-
-  void GetStartEndTimestamps(int64* start, int64* end);
-  int64 GetDeltaElapsed();
-
- private:
-  unsigned int queries_[2];
-  int64 offset_ = 0;
-  bool end_requested_ = false;
-  GPUTiming* gpu_timing_;
-
-  DISALLOW_COPY_AND_ASSIGN(GPUTimer);
-};
-
-// GPUTiming contains all the gl timing logic that is not specific
-// to a single GPUTimer.
-class GPU_EXPORT GPUTiming {
- public:
-  enum TimerType {
-    kTimerTypeInvalid = -1,
-
-    kTimerTypeARB,      // ARB_timer_query
-    kTimerTypeDisjoint  // EXT_disjoint_timer_query
-  };
-
-  GPUTiming();
-  virtual ~GPUTiming();
-
-  bool Initialize(gfx::GLContext* context);
-  bool IsAvailable();
-
-  // CheckAndResetTimerErrors has to be called before reading timestamps
-  // from GPUTimers instances and after making sure all the timers
-  // were available.
-  // If the returned value is false, all the previous timers should be
-  // discarded.
-  bool CheckAndResetTimerErrors();
-
-  const char* GetTimerTypeName() const;
-
-  // Returns the offset between the current gpu time and the cpu time.
-  int64 CalculateTimerOffset();
-  void InvalidateTimerOffset();
-
-  void SetCpuTimeForTesting(const base::Callback<int64(void)>& cpu_time);
-  void SetOffsetForTesting(int64 offset, bool cache_it);
-  void SetTimerTypeForTesting(TimerType type);
-
- private:
-  TimerType timer_type_ = kTimerTypeInvalid;
-  int64 offset_ = 0;  // offset cache when timer_type_ == kTimerTypeARB
-  bool offset_valid_ = false;
-  base::Callback<int64(void)> cpu_time_for_testing_;
-  friend class GPUTimer;
-  DISALLOW_COPY_AND_ASSIGN(GPUTiming);
-};
-}  // namespace gpu
-
-#endif  // GPU_COMMAND_BUFFER_SERVICE_GPU_TIMING_H_