Remove std::string histogram name from HistogramBase object.

base/metrics/histogram.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.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 
 // It supports calls to accumulate either time intervals (which are processed
 // as integral number of milliseconds), or arbitrary integral units.
@@ skipping 122 matching lines @@
                                    uint32_t bucket_count,
                                    int32_t flags);
   static HistogramBase* FactoryTimeGet(const char* name,
                                        base::TimeDelta minimum,
                                        base::TimeDelta maximum,
                                        uint32_t bucket_count,
                                        int32_t flags);
 
   // Create a histogram using data in persistent storage.
   static std::unique_ptr<HistogramBase> PersistentCreate(
-      const std::string& name,
+      const char* name,
       Sample minimum,
       Sample maximum,
       const BucketRanges* ranges,
       const DelayedPersistentAllocation& counts,
       const DelayedPersistentAllocation& logged_counts,
       HistogramSamples::Metadata* meta,
       HistogramSamples::Metadata* logged_meta);
 
   static void InitializeBucketRanges(Sample minimum,
                                      Sample maximum,
@@ skipping 56 matching lines @@
  protected:
   // This class, defined entirely within the .cc file, contains all the
   // common logic for building a Histogram and can be overridden by more
   // specific types to alter details of how the creation is done. It is
   // defined as an embedded class (rather than an anonymous one) so it
   // can access the protected constructors.
   class Factory;
 
   // |ranges| should contain the underflow and overflow buckets. See top
   // comments for example.
-  Histogram(const std::string& name,
+  Histogram(const char* name,
             Sample minimum,
             Sample maximum,
             const BucketRanges* ranges);
 
   // Traditionally, histograms allocate their own memory for the bucket
   // vector but "shared" histograms use memory regions allocated from a
   // special memory segment that is passed in here.  It is assumed that
   // the life of this memory is managed externally and exceeds the lifetime
   // of this object. Practically, this memory is never released until the
   // process exits and the OS cleans it up.
-  Histogram(const std::string& name,
+  Histogram(const char* name,
             Sample minimum,
             Sample maximum,
             const BucketRanges* ranges,
             const DelayedPersistentAllocation& counts,
             const DelayedPersistentAllocation& logged_counts,
             HistogramSamples::Metadata* meta,
             HistogramSamples::Metadata* logged_meta);
 
   // HistogramBase implementation:
   bool SerializeInfoImpl(base::Pickle* pickle) const override;
@@ skipping 108 matching lines @@
                                    uint32_t bucket_count,
                                    int32_t flags);
   static HistogramBase* FactoryTimeGet(const char* name,
                                        TimeDelta minimum,
                                        TimeDelta maximum,
                                        uint32_t bucket_count,
                                        int32_t flags);
 
   // Create a histogram using data in persistent storage.
   static std::unique_ptr<HistogramBase> PersistentCreate(
-      const std::string& name,
+      const char* name,
       Sample minimum,
       Sample maximum,
       const BucketRanges* ranges,
       const DelayedPersistentAllocation& counts,
       const DelayedPersistentAllocation& logged_counts,
       HistogramSamples::Metadata* meta,
       HistogramSamples::Metadata* logged_meta);
 
   struct DescriptionPair {
     Sample sample;
@@ skipping 16 matching lines @@
   static void InitializeBucketRanges(Sample minimum,
                                      Sample maximum,
                                      BucketRanges* ranges);
 
   // Overridden from Histogram:
   HistogramType GetHistogramType() const override;
 
  protected:
   class Factory;
 
-  LinearHistogram(const std::string& name,
+  LinearHistogram(const char* name,
                   Sample minimum,
                   Sample maximum,
                   const BucketRanges* ranges);
 
-  LinearHistogram(const std::string& name,
+  LinearHistogram(const char* name,
                   Sample minimum,
                   Sample maximum,
                   const BucketRanges* ranges,
                   const DelayedPersistentAllocation& counts,
                   const DelayedPersistentAllocation& logged_counts,
                   HistogramSamples::Metadata* meta,
                   HistogramSamples::Metadata* logged_meta);
 
   double GetBucketSize(Count current, uint32_t i) const override;
 
@@ skipping 26 matching lines @@
  public:
   static HistogramBase* FactoryGet(const std::string& name, int32_t flags);
 
   // Overload of the above function that takes a const char* |name| param,
   // to avoid code bloat from the std::string constructor being inlined into
   // call sites.
   static HistogramBase* FactoryGet(const char* name, int32_t flags);
 
   // Create a histogram using data in persistent storage.
   static std::unique_ptr<HistogramBase> PersistentCreate(
-      const std::string& name,
+      const char* name,
       const BucketRanges* ranges,
       const DelayedPersistentAllocation& counts,
       const DelayedPersistentAllocation& logged_counts,
       HistogramSamples::Metadata* meta,
       HistogramSamples::Metadata* logged_meta);
 
   HistogramType GetHistogramType() const override;
 
  protected:
   class Factory;
 
  private:
-  BooleanHistogram(const std::string& name, const BucketRanges* ranges);
-  BooleanHistogram(const std::string& name,
+  BooleanHistogram(const char* name, const BucketRanges* ranges);
+  BooleanHistogram(const char* name,
                    const BucketRanges* ranges,
                    const DelayedPersistentAllocation& counts,
                    const DelayedPersistentAllocation& logged_counts,
                    HistogramSamples::Metadata* meta,
                    HistogramSamples::Metadata* logged_meta);
 
   friend BASE_EXPORT HistogramBase* DeserializeHistogramInfo(
       base::PickleIterator* iter);
   static HistogramBase* DeserializeInfoImpl(base::PickleIterator* iter);
 
@@ skipping 15 matching lines @@
 
   // Overload of the above function that takes a const char* |name| param,
   // to avoid code bloat from the std::string constructor being inlined into
   // call sites.
   static HistogramBase* FactoryGet(const char* name,
                                    const std::vector<Sample>& custom_ranges,
                                    int32_t flags);
 
   // Create a histogram using data in persistent storage.
   static std::unique_ptr<HistogramBase> PersistentCreate(
-      const std::string& name,
+      const char* name,
       const BucketRanges* ranges,
       const DelayedPersistentAllocation& counts,
       const DelayedPersistentAllocation& logged_counts,
       HistogramSamples::Metadata* meta,
       HistogramSamples::Metadata* logged_meta);
 
   // Overridden from Histogram:
   HistogramType GetHistogramType() const override;
 
   // Helper method for transforming an array of valid enumeration values
   // to the std::vector<int> expected by UMA_HISTOGRAM_CUSTOM_ENUMERATION.
   // This function ensures that a guard bucket exists right after any
   // valid sample value (unless the next higher sample is also a valid value),
   // so that invalid samples never fall into the same bucket as valid samples.
   // TODO(kaiwang): Change name to ArrayToCustomEnumRanges.
   static std::vector<Sample> ArrayToCustomRanges(const Sample* values,
                                                  uint32_t num_values);
  protected:
   class Factory;
 
-  CustomHistogram(const std::string& name,
-                  const BucketRanges* ranges);
+  CustomHistogram(const char* name, const BucketRanges* ranges);
 
-  CustomHistogram(const std::string& name,
+  CustomHistogram(const char* name,
                   const BucketRanges* ranges,
                   const DelayedPersistentAllocation& counts,
                   const DelayedPersistentAllocation& logged_counts,
                   HistogramSamples::Metadata* meta,
                   HistogramSamples::Metadata* logged_meta);
 
   // HistogramBase implementation:
   bool SerializeInfoImpl(base::Pickle* pickle) const override;
 
   double GetBucketSize(Count current, uint32_t i) const override;
 
  private:
   friend BASE_EXPORT HistogramBase* DeserializeHistogramInfo(
       base::PickleIterator* iter);
   static HistogramBase* DeserializeInfoImpl(base::PickleIterator* iter);
 
   static bool ValidateCustomRanges(const std::vector<Sample>& custom_ranges);
 
   DISALLOW_COPY_AND_ASSIGN(CustomHistogram);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_HISTOGRAM_H_