Embed a single sample in histogram metadata.

base/metrics/histogram.cc

Index: base/metrics/histogram.cc
diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index e1d0df6736fa326b5f74c717974f40bf711be0c9..bf22ffcc2e3fedc3f57715d5444f5ccf361ffc62 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -275,14 +275,12 @@ std::unique_ptr<HistogramBase> Histogram::PersistentCreate(
     Sample minimum,
     Sample maximum,
     const BucketRanges* ranges,
-    HistogramBase::AtomicCount* counts,
-    HistogramBase::AtomicCount* logged_counts,
-    uint32_t counts_size,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
     HistogramSamples::Metadata* meta,
     HistogramSamples::Metadata* logged_meta) {
   return WrapUnique(new Histogram(name, minimum, maximum, ranges, counts,
-                                  logged_counts, counts_size, meta,
-                                  logged_meta));
+                                  logged_counts, meta, logged_meta));
 }
 
 // Calculate what range of values are held in each bucket.
@@ -512,20 +510,19 @@ Histogram::Histogram(const std::string& name,
                      Sample minimum,
                      Sample maximum,
                      const BucketRanges* ranges,
-                     HistogramBase::AtomicCount* counts,
-                     HistogramBase::AtomicCount* logged_counts,
-                     uint32_t counts_size,
+                     const DelayedPersistentAllocation& counts,
+                     const DelayedPersistentAllocation& logged_counts,
                      HistogramSamples::Metadata* meta,
                      HistogramSamples::Metadata* logged_meta)
-  : HistogramBase(name),
-    bucket_ranges_(ranges),
-    declared_min_(minimum),
-    declared_max_(maximum) {
+    : HistogramBase(name),
+      bucket_ranges_(ranges),
+      declared_min_(minimum),
+      declared_max_(maximum) {
   if (ranges) {
-    samples_.reset(new SampleVector(HashMetricName(name),
-                                    counts, counts_size, meta, ranges));
-    logged_samples_.reset(new SampleVector(samples_->id(), logged_counts,
-                                           counts_size, logged_meta, ranges));
+    samples_.reset(
+        new PersistentSampleVector(HashMetricName(name), ranges, meta, counts));
+    logged_samples_.reset(new PersistentSampleVector(
+        samples_->id(), ranges, logged_meta, logged_counts));
   }
 }
 
@@ -656,7 +653,7 @@ void Histogram::WriteAsciiImpl(bool graph_it,
   DCHECK_EQ(sample_count, past);
 }
 
-double Histogram::GetPeakBucketSize(const SampleVector& samples) const {
+double Histogram::GetPeakBucketSize(const SampleVectorBase& samples) const {
   double max = 0;
   for (uint32_t i = 0; i < bucket_count() ; ++i) {
     double current_size = GetBucketSize(samples.GetCountAtIndex(i), i);
@@ -666,7 +663,7 @@ double Histogram::GetPeakBucketSize(const SampleVector& samples) const {
   return max;
 }
 
-void Histogram::WriteAsciiHeader(const SampleVector& samples,
+void Histogram::WriteAsciiHeader(const SampleVectorBase& samples,
                                  Count sample_count,
                                  std::string* output) const {
   StringAppendF(output,
@@ -815,14 +812,12 @@ std::unique_ptr<HistogramBase> LinearHistogram::PersistentCreate(
     Sample minimum,
     Sample maximum,
     const BucketRanges* ranges,
-    HistogramBase::AtomicCount* counts,
-    HistogramBase::AtomicCount* logged_counts,
-    uint32_t counts_size,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
     HistogramSamples::Metadata* meta,
     HistogramSamples::Metadata* logged_meta) {
-  return WrapUnique(new LinearHistogram(name, minimum, maximum, ranges,
-                                              counts, logged_counts,
-                                              counts_size, meta, logged_meta));
+  return WrapUnique(new LinearHistogram(name, minimum, maximum, ranges, counts,
+                                        logged_counts, meta, logged_meta));
 }
 
 HistogramBase* LinearHistogram::FactoryGetWithRangeDescription(
@@ -851,17 +846,23 @@ LinearHistogram::LinearHistogram(const std::string& name,
     : Histogram(name, minimum, maximum, ranges) {
 }
 
-LinearHistogram::LinearHistogram(const std::string& name,
-                                 Sample minimum,
-                                 Sample maximum,
-                                 const BucketRanges* ranges,
-                                 HistogramBase::AtomicCount* counts,
-                                 HistogramBase::AtomicCount* logged_counts,
-                                 uint32_t counts_size,
-                                 HistogramSamples::Metadata* meta,
-                                 HistogramSamples::Metadata* logged_meta)
-    : Histogram(name, minimum, maximum, ranges, counts, logged_counts,
-                counts_size, meta, logged_meta) {}
+LinearHistogram::LinearHistogram(
+    const std::string& name,
+    Sample minimum,
+    Sample maximum,
+    const BucketRanges* ranges,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
+    HistogramSamples::Metadata* meta,
+    HistogramSamples::Metadata* logged_meta)
+    : Histogram(name,
+                minimum,
+                maximum,
+                ranges,
+                counts,
+                logged_counts,
+                meta,
+                logged_meta) {}
 
 double LinearHistogram::GetBucketSize(Count current, uint32_t i) const {
   DCHECK_GT(ranges(i + 1), ranges(i));
@@ -961,12 +962,12 @@ HistogramBase* BooleanHistogram::FactoryGet(const char* name, int32_t flags) {
 std::unique_ptr<HistogramBase> BooleanHistogram::PersistentCreate(
     const std::string& name,
     const BucketRanges* ranges,
-    HistogramBase::AtomicCount* counts,
-    HistogramBase::AtomicCount* logged_counts,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
     HistogramSamples::Metadata* meta,
     HistogramSamples::Metadata* logged_meta) {
-  return WrapUnique(new BooleanHistogram(
-      name, ranges, counts, logged_counts, meta, logged_meta));
+  return WrapUnique(new BooleanHistogram(name, ranges, counts, logged_counts,
+                                         meta, logged_meta));
 }
 
 HistogramType BooleanHistogram::GetHistogramType() const {
@@ -977,13 +978,20 @@ BooleanHistogram::BooleanHistogram(const std::string& name,
                                    const BucketRanges* ranges)
     : LinearHistogram(name, 1, 2, ranges) {}
 
-BooleanHistogram::BooleanHistogram(const std::string& name,
-                                   const BucketRanges* ranges,
-                                   HistogramBase::AtomicCount* counts,
-                                   HistogramBase::AtomicCount* logged_counts,
-                                   HistogramSamples::Metadata* meta,
-                                   HistogramSamples::Metadata* logged_meta)
-    : LinearHistogram(name, 1, 2, ranges, counts, logged_counts, 2, meta,
+BooleanHistogram::BooleanHistogram(
+    const std::string& name,
+    const BucketRanges* ranges,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
+    HistogramSamples::Metadata* meta,
+    HistogramSamples::Metadata* logged_meta)
+    : LinearHistogram(name,
+                      1,
+                      2,
+                      ranges,
+                      counts,
+                      logged_counts,
+                      meta,
                       logged_meta) {}
 
 HistogramBase* BooleanHistogram::DeserializeInfoImpl(PickleIterator* iter) {
@@ -1068,13 +1076,12 @@ HistogramBase* CustomHistogram::FactoryGet(
 std::unique_ptr<HistogramBase> CustomHistogram::PersistentCreate(
     const std::string& name,
     const BucketRanges* ranges,
-    HistogramBase::AtomicCount* counts,
-    HistogramBase::AtomicCount* logged_counts,
-    uint32_t counts_size,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
     HistogramSamples::Metadata* meta,
     HistogramSamples::Metadata* logged_meta) {
-  return WrapUnique(new CustomHistogram(
-      name, ranges, counts, logged_counts, counts_size, meta, logged_meta));
+  return WrapUnique(new CustomHistogram(name, ranges, counts, logged_counts,
+                                        meta, logged_meta));
 }
 
 HistogramType CustomHistogram::GetHistogramType() const {
@@ -1103,20 +1110,19 @@ CustomHistogram::CustomHistogram(const std::string& name,
                 ranges->range(ranges->bucket_count() - 1),
                 ranges) {}
 
-CustomHistogram::CustomHistogram(const std::string& name,
-                                 const BucketRanges* ranges,
-                                 HistogramBase::AtomicCount* counts,
-                                 HistogramBase::AtomicCount* logged_counts,
-                                 uint32_t counts_size,
-                                 HistogramSamples::Metadata* meta,
-                                 HistogramSamples::Metadata* logged_meta)
+CustomHistogram::CustomHistogram(
+    const std::string& name,
+    const BucketRanges* ranges,
+    const DelayedPersistentAllocation& counts,
+    const DelayedPersistentAllocation& logged_counts,
+    HistogramSamples::Metadata* meta,
+    HistogramSamples::Metadata* logged_meta)
     : Histogram(name,
                 ranges->range(1),
                 ranges->range(ranges->bucket_count() - 1),
                 ranges,
                 counts,
                 logged_counts,
-                counts_size,
                 meta,
                 logged_meta) {}