Telemetry startup tests: Add more histograms to startup tests

* Track a couple more histograms in telemetry-based startup test.
* Make histograms report average value in JSON, in the case of the histograms we're interested in, only a single value is recorded so the average is the exact value and we aren't limited in resolution by the bucket width.
* Remove unneeded _Exact histogram.

BUG=None

Review URL: https://chromiumcodereview.appspot.com/14632003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@199435 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 13 insertions, 3 deletions

diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index da12ccb..bb2ee9b 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -487,9 +487,12 @@ void Histogram::GetParameters(DictionaryValue* params) const {
   params->SetInteger("bucket_count", static_cast<int>(bucket_count()));
 }
 
-void Histogram::GetCountAndBucketData(Count* count, ListValue* buckets) const {
+void Histogram::GetCountAndBucketData(Count* count,
+                                      int64* sum,
+                                      ListValue* buckets) const {
   scoped_ptr<SampleVector> snapshot = SnapshotSampleVector();
   *count = snapshot->TotalCount();
+  *sum = snapshot->sum();
   size_t index = 0;
   for (size_t i = 0; i < bucket_count(); ++i) {
     Sample count = snapshot->GetCountAtIndex(i);
diff --git a/base/metrics/histogram.h b/base/metrics/histogram.h
index 8d059f9..72da2e0 100644
--- a/base/metrics/histogram.h
+++ b/base/metrics/histogram.h
@@ -515,6 +515,7 @@ class BASE_EXPORT Histogram : public HistogramBase {
   virtual void GetParameters(DictionaryValue* params) const OVERRIDE;
 
   virtual void GetCountAndBucketData(Count* count,
+                                     int64* sum,
                                      ListValue* buckets) const OVERRIDE;
 
   // Does not own this object. Should get from StatisticsRecorder.
diff --git a/base/metrics/histogram_base.cc b/base/metrics/histogram_base.cc
index 51689a8..8599f59 100644
--- a/base/metrics/histogram_base.cc
+++ b/base/metrics/histogram_base.cc
@@ -109,8 +109,9 @@ int HistogramBase::FindCorruption(const HistogramSamples& samples) const {
 
 void HistogramBase::WriteJSON(std::string* output) const {
   Count count;
+  int64 sum;
   scoped_ptr<ListValue> buckets(new ListValue());
-  GetCountAndBucketData(&count, buckets.get());
+  GetCountAndBucketData(&count, &sum, buckets.get());
   scoped_ptr<DictionaryValue> parameters(new DictionaryValue());
   GetParameters(parameters.get());
 
@@ -118,6 +119,7 @@ void HistogramBase::WriteJSON(std::string* output) const {
   DictionaryValue root;
   root.SetString("name", histogram_name());
   root.SetInteger("count", count);
+  root.SetDouble("sum", sum);
   root.SetInteger("flags", flags());
   root.Set("params", parameters.release());
   root.Set("buckets", buckets.release());
diff --git a/base/metrics/histogram_base.h b/base/metrics/histogram_base.h
index 2fa846e..a133fa5 100644
--- a/base/metrics/histogram_base.h
+++ b/base/metrics/histogram_base.h
@@ -139,8 +139,10 @@ protected:
   virtual void GetParameters(DictionaryValue* params) const = 0;
 
   // Writes information about the current (non-empty) buckets and their sample
-  // counts to |buckets| and the total sample count to |count|.
+  // counts to |buckets|, the total sample count to |count| and the total sum
+  // to |sum|.
   virtual void GetCountAndBucketData(Count* count,
+                                     int64* sum,
                                      ListValue* buckets) const = 0;
 
   //// Produce actual graph (set of blank vs non blank char's) for a bucket.
diff --git a/base/metrics/sparse_histogram.cc b/base/metrics/sparse_histogram.cc
index df361f7..dd98e58 100644
--- a/base/metrics/sparse_histogram.cc
+++ b/base/metrics/sparse_histogram.cc
@@ -105,6 +105,7 @@ void SparseHistogram::GetParameters(DictionaryValue* params) const {
 }
 
 void SparseHistogram::GetCountAndBucketData(Count* count,
+                                            int64* sum,
                                             ListValue* buckets) const {
   // TODO(kaiwang): Implement. (See HistogramBase::WriteJSON.)
 }
diff --git a/base/metrics/sparse_histogram.h b/base/metrics/sparse_histogram.h
index 4de2002..870b06b 100644
--- a/base/metrics/sparse_histogram.h
+++ b/base/metrics/sparse_histogram.h
@@ -88,6 +88,7 @@ class BASE_EXPORT_PRIVATE SparseHistogram : public HistogramBase {
 
   virtual void GetParameters(DictionaryValue* params) const OVERRIDE;
   virtual void GetCountAndBucketData(Count* count,
+                                     int64* sum,
                                      ListValue* buckets) const OVERRIDE;
 
   // Helpers for emitting Ascii graphic.  Each method appends data to output.