Remove std::string histogram name from HistogramBase object.

base/metrics/histogram.cc

Index: base/metrics/histogram.cc
diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index fdc4c1a2c3390ec9da85bf649b0c44d4abccc0ab..daa4654c84a931d89360cc32d57a8cd39e3255b8 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -137,7 +137,8 @@ class Histogram::Factory {
   // Allocate the correct Histogram object off the heap (in case persistent
   // memory is not available).
   virtual std::unique_ptr<HistogramBase> HeapAlloc(const BucketRanges* ranges) {
-    return WrapUnique(new Histogram(name_, minimum_, maximum_, ranges));
+    return WrapUnique(
+        new Histogram(GetPermanentName(name_), minimum_, maximum_, ranges));
   }
 
   // Perform any required datafill on the just-created histogram.  If
@@ -287,7 +288,7 @@ HistogramBase* Histogram::FactoryTimeGet(const char* name,
 }
 
 std::unique_ptr<HistogramBase> Histogram::PersistentCreate(
-    const std::string& name,
+    const char* name,
     Sample minimum,
     Sample maximum,
     const BucketRanges* ranges,
@@ -398,7 +399,7 @@ uint32_t Histogram::bucket_count() const {
 }
 
 // static
-bool Histogram::InspectConstructionArguments(const std::string& name,
+bool Histogram::InspectConstructionArguments(StringPiece name,
                                              Sample* minimum,
                                              Sample* maximum,
                                              uint32_t* bucket_count) {
@@ -584,7 +585,7 @@ bool Histogram::ValidateHistogramContents(bool crash_if_invalid,
 
   // Abort if a problem is found (except "flags", which could legally be zero).
   const std::string debug_string = base::StringPrintf(
-      "%s/%" PRIu32 "#%d", histogram_name().c_str(), bad_fields, identifier);
+      "%s/%" PRIu32 "#%d", histogram_name(), bad_fields, identifier);
 #if !defined(OS_NACL)
   // Temporary for https://crbug.com/736675.
   base::debug::ScopedCrashKey crash_key("bad_histogram", debug_string);
@@ -605,7 +606,7 @@ bool Histogram::SerializeInfoImpl(Pickle* pickle) const {
 }
 
 // TODO(bcwhite): Remove minimum/maximum parameters from here and call chain.
-Histogram::Histogram(const std::string& name,
+Histogram::Histogram(const char* name,
                      Sample minimum,
                      Sample maximum,
                      const BucketRanges* ranges)
@@ -616,7 +617,7 @@ Histogram::Histogram(const std::string& name,
   logged_samples_.reset(new SampleVector(unlogged_samples_->id(), ranges));
 }
 
-Histogram::Histogram(const std::string& name,
+Histogram::Histogram(const char* name,
                      Sample minimum,
                      Sample maximum,
                      const BucketRanges* ranges,
@@ -787,9 +788,7 @@ double Histogram::GetPeakBucketSize(const SampleVectorBase& samples) const {
 void Histogram::WriteAsciiHeader(const SampleVectorBase& samples,
                                  Count sample_count,
                                  std::string* output) const {
-  StringAppendF(output,
-                "Histogram: %s recorded %d samples",
-                histogram_name().c_str(),
+  StringAppendF(output, "Histogram: %s recorded %d samples", histogram_name(),
                 sample_count);
   if (sample_count == 0) {
     DCHECK_EQ(samples.sum(), 0);
@@ -870,7 +869,8 @@ class LinearHistogram::Factory : public Histogram::Factory {
 
   std::unique_ptr<HistogramBase> HeapAlloc(
       const BucketRanges* ranges) override {
-    return WrapUnique(new LinearHistogram(name_, minimum_, maximum_, ranges));
+    return WrapUnique(new LinearHistogram(GetPermanentName(name_), minimum_,
+                                          maximum_, ranges));
   }
 
   void FillHistogram(HistogramBase* base_histogram) override {
@@ -898,8 +898,8 @@ HistogramBase* LinearHistogram::FactoryGet(const std::string& name,
                                            Sample maximum,
                                            uint32_t bucket_count,
                                            int32_t flags) {
-  return FactoryGetWithRangeDescription(name, minimum, maximum, bucket_count,
-                                        flags, nullptr);
+  return FactoryGetWithRangeDescription(
+      name, minimum, maximum, bucket_count, flags, NULL);
 }
 
 HistogramBase* LinearHistogram::FactoryTimeGet(const std::string& name,
@@ -930,7 +930,7 @@ HistogramBase* LinearHistogram::FactoryTimeGet(const char* name,
 }
 
 std::unique_ptr<HistogramBase> LinearHistogram::PersistentCreate(
-    const std::string& name,
+    const char* name,
     Sample minimum,
     Sample maximum,
     const BucketRanges* ranges,
@@ -961,15 +961,14 @@ HistogramType LinearHistogram::GetHistogramType() const {
   return LINEAR_HISTOGRAM;
 }
 
-LinearHistogram::LinearHistogram(const std::string& name,
+LinearHistogram::LinearHistogram(const char* name,
                                  Sample minimum,
                                  Sample maximum,
                                  const BucketRanges* ranges)
-    : Histogram(name, minimum, maximum, ranges) {
-}
+    : Histogram(name, minimum, maximum, ranges) {}
 
 LinearHistogram::LinearHistogram(
-    const std::string& name,
+    const char* name,
     Sample minimum,
     Sample maximum,
     const BucketRanges* ranges,
@@ -1069,7 +1068,7 @@ class BooleanHistogram::Factory : public Histogram::Factory {
 
   std::unique_ptr<HistogramBase> HeapAlloc(
       const BucketRanges* ranges) override {
-    return WrapUnique(new BooleanHistogram(name_, ranges));
+    return WrapUnique(new BooleanHistogram(GetPermanentName(name_), ranges));
   }
 
  private:
@@ -1086,7 +1085,7 @@ HistogramBase* BooleanHistogram::FactoryGet(const char* name, int32_t flags) {
 }
 
 std::unique_ptr<HistogramBase> BooleanHistogram::PersistentCreate(
-    const std::string& name,
+    const char* name,
     const BucketRanges* ranges,
     const DelayedPersistentAllocation& counts,
     const DelayedPersistentAllocation& logged_counts,
@@ -1100,12 +1099,11 @@ HistogramType BooleanHistogram::GetHistogramType() const {
   return BOOLEAN_HISTOGRAM;
 }
 
-BooleanHistogram::BooleanHistogram(const std::string& name,
-                                   const BucketRanges* ranges)
+BooleanHistogram::BooleanHistogram(const char* name, const BucketRanges* ranges)
     : LinearHistogram(name, 1, 2, ranges) {}
 
 BooleanHistogram::BooleanHistogram(
-    const std::string& name,
+    const char* name,
     const BucketRanges* ranges,
     const DelayedPersistentAllocation& counts,
     const DelayedPersistentAllocation& logged_counts,
@@ -1177,7 +1175,7 @@ class CustomHistogram::Factory : public Histogram::Factory {
 
   std::unique_ptr<HistogramBase> HeapAlloc(
       const BucketRanges* ranges) override {
-    return WrapUnique(new CustomHistogram(name_, ranges));
+    return WrapUnique(new CustomHistogram(GetPermanentName(name_), ranges));
   }
 
  private:
@@ -1203,7 +1201,7 @@ HistogramBase* CustomHistogram::FactoryGet(
 }
 
 std::unique_ptr<HistogramBase> CustomHistogram::PersistentCreate(
-    const std::string& name,
+    const char* name,
     const BucketRanges* ranges,
     const DelayedPersistentAllocation& counts,
     const DelayedPersistentAllocation& logged_counts,
@@ -1232,15 +1230,14 @@ std::vector<Sample> CustomHistogram::ArrayToCustomRanges(
   return all_values;
 }
 
-CustomHistogram::CustomHistogram(const std::string& name,
-                                 const BucketRanges* ranges)
+CustomHistogram::CustomHistogram(const char* name, const BucketRanges* ranges)
     : Histogram(name,
                 ranges->range(1),
                 ranges->range(ranges->bucket_count() - 1),
                 ranges) {}
 
 CustomHistogram::CustomHistogram(
-    const std::string& name,
+    const char* name,
     const BucketRanges* ranges,
     const DelayedPersistentAllocation& counts,
     const DelayedPersistentAllocation& logged_counts,