Moved scoped_histogram_timer to the main histogram_macros.h.

media/base/scoped_histogram_timer.h

-// Copyright 2013 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 MEDIA_BASE_SCOPED_HISTOGRAM_TIMER_H_
-#define MEDIA_BASE_SCOPED_HISTOGRAM_TIMER_H_
-
-#include "base/metrics/histogram.h"
-#include "base/time/time.h"
-
-// Scoped class which logs its time on this earth as a UMA statistic.  Must be
-// a #define macro since UMA macros prevent variables as names.  The nested
-// macro is necessary to expand __COUNTER__ to an actual value.
-#define SCOPED_UMA_HISTOGRAM_TIMER(name) \
-  SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, __COUNTER__)
-
-#define SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, key) \
-  SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, key)
-
-#define SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, key) \
-  class ScopedHistogramTimer##key { \
-   public: \
-    ScopedHistogramTimer##key() : constructed_(base::TimeTicks::Now()) {} \
-    ~ScopedHistogramTimer##key() { \
-      base::TimeDelta elapsed = base::TimeTicks::Now() - constructed_; \
-      UMA_HISTOGRAM_TIMES(name, elapsed); \
-    } \
-   private: \
-    base::TimeTicks constructed_; \
-  } scoped_histogram_timer_##key
-
-#endif  // MEDIA_BASE_SCOPED_HISTOGRAM_TIMER_H_