Update from https://crrev.com/316786

gpu/command_buffer/service/gpu_timing.h

Index: gpu/command_buffer/service/gpu_timing.h
diff --git a/gpu/command_buffer/service/gpu_timing.h b/gpu/command_buffer/service/gpu_timing.h
new file mode 100644
index 0000000000000000000000000000000000000000..1d9ecf690902e2725ff14f97a96f129ee95e1e2b
--- /dev/null
+++ b/gpu/command_buffer/service/gpu_timing.h
@@ -0,0 +1,85 @@
+// 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"
+#include "ui/gl/gl_bindings.h"
+
+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:
+  GLuint 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_