Add UMA.IsClonedInstall boolean histogram.

components/metrics/metrics_log.cc

Index: components/metrics/metrics_log.cc
diff --git a/components/metrics/metrics_log.cc b/components/metrics/metrics_log.cc
index 0856f31f3b86314788faeb600d7abfd761146962..741ea68545d8a105290e7961451cf599f0baa3aa 100644
--- a/components/metrics/metrics_log.cc
+++ b/components/metrics/metrics_log.cc
@@ -297,6 +297,9 @@ void MetricsLog::RecordStabilityMetrics(
 
 void MetricsLog::RecordGeneralMetrics(
     const std::vector<MetricsProvider*>& metrics_providers) {
+  if (local_state_->GetBoolean(prefs::kMetricsResetIds))
+    UMA_HISTOGRAM_BOOLEAN("UMA.IsClonedInstall", true);

[rkaplow, 2017/02/06 16:20:26]

what about reporting the false case? You think not worth it?

[Alexei Svitkine (slow), 2017/02/06 16:26:03]

I discuss this in the CL description.

I don't think it warrants the banwidth use for everyone else. Also, with the new
changes to user counts toggle on histograms dashboard that YK is making, we can
easily compare to all record counts.

+
   for (size_t i = 0; i < metrics_providers.size(); ++i)
     metrics_providers[i]->ProvideGeneralMetrics(uma_proto());
 }