Revert 148055 - Move CachedRanges out and add support for checksum.

base/metrics/bucket_ranges.h

-// Copyright (c) 2012 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.
-//
-// BucketRanges stores the vector of ranges that delimit what samples are
-// tallied in the corresponding buckets of a histogram. Histograms that have
-// same ranges for all their corresponding buckets should share the same
-// BucketRanges object.
-//
-// E.g. A 5 buckets LinearHistogram with 1 as minimal value and 4 as maximal
-// value will need a BucketRanges with 6 ranges:
-// 0, 1, 2, 3, 4, INT_MAX
-//
-// TODO(kaiwang): Currently we keep all negative values in 0~1 bucket. Consider
-// changing 0 to INT_MIN.
-
-#ifndef BASE_METRICS_BUCKET_RANGES_H_
-#define BASE_METRICS_BUCKET_RANGES_H_
-
-#include <vector>
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/gtest_prod_util.h"
-#include "base/metrics/histogram_base.h"
-
-namespace base {
-
-class BASE_EXPORT_PRIVATE BucketRanges {
- public:
-  typedef std::vector<HistogramBase::Sample> Ranges;
-
-  BucketRanges(size_t num_ranges);
-  ~BucketRanges();
-
-  size_t size() const { return ranges_.size(); }
-  HistogramBase::Sample range(size_t i) const { return ranges_[i]; }
-  void set_range(size_t i, HistogramBase::Sample value);
-  uint32 checksum() const { return checksum_; }
-  void set_checksum(uint32 checksum) { checksum_ = checksum; }
-
-  // Checksum methods to verify whether the ranges are corrupted (e.g. bad
-  // memory access).
-  uint32 CalculateChecksum();
-  bool HasValidChecksum();
-  void ResetChecksum();
-
-  // Return true iff |other| object has same ranges_ as |this| object's ranges_.
-  bool Equals(const BucketRanges* other) const;
-
- private:
-  // A monotonically increasing list of values which determine which bucket to
-  // put a sample into.  For each index, show the smallest sample that can be
-  // added to the corresponding bucket.
-  Ranges ranges_;
-
-  // Checksum for the conntents of ranges_.  Used to detect random over-writes
-  // of our data, and to quickly see if some other BucketRanges instance is
-  // possibly Equal() to this instance.
-  // TODO(kaiwang): Consider change this to uint64. Because we see a lot of
-  // noise on UMA dashboard.
-  uint32 checksum_;
-
-  DISALLOW_COPY_AND_ASSIGN(BucketRanges);
-};
-
-}  // namespace base
-
-#endif  // BASE_METRICS_BUCKET_RANGES_H_