Bug 682869 - introduce Telemetry::AccumulateTimeDelta. r=tglek

--HG--
extra : rebase_source : e7724d2c9780d4afebd83ec0978f9feccb86ce35

toolkit/components/telemetry/Telemetry.cpp

@@ -411,6 +411,13 @@ Accumulate(ID aHistogram, PRUint32 aSample)
     h->Add(aSample);
 }
 
+void
+AccumulateTimeDelta(ID aHistogram, TimeStamp start, TimeStamp end)
+{
+  Accumulate(aHistogram,
+             static_cast<PRUint32>((end - start).ToMilliseconds()));
+}
+
 base::Histogram*
 GetHistogramById(ID id)
 {

toolkit/components/telemetry/Telemetry.h

@@ -66,6 +66,15 @@ HistogramCount
  */
 void Accumulate(ID id, PRUint32 sample);
 
+/**
+ * Adds time delta in milliseconds to a histogram defined in TelemetryHistograms.h
+ *
+ * @param id - histogram id
+ * @param start - start time
+ * @param end - end time
+ */
+void AccumulateTimeDelta(ID id, TimeStamp start, TimeStamp end = TimeStamp::Now());
+
 /**
  * Return a raw Histogram for direct manipulation for users who can not use Accumulate().
  */