Android: Add histogram to track renderer crashes

Crash team is preparing to switch stats from being tracked using
histograms to the stability proto. We would like to be confident that we
will not lose accuracy when migrating the old stability proto metric to
a new histogram.

Bug: 726513
Change-Id: I0e3b6eac219b731e9eb815723e882c7d45bfdbe4
Reviewed-on: https://chromium-review.googlesource.com/517864Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476288}

chrome/browser/android/metrics/uma_session_stats.cc

@@ -151,6 +151,8 @@ static void LogRendererCrash(JNIEnv*, const JavaParamRef<jclass>&) {
   DCHECK(pref);
   int value = pref->GetInteger(metrics::prefs::kStabilityRendererCrashCount);
   pref->SetInteger(metrics::prefs::kStabilityRendererCrashCount, value + 1);
+  // Migrate proto to histogram to repurpose proto count.
+  UMA_HISTOGRAM_BOOLEAN("Stability.Android.RendererCrash", true);
 }
 
 static void RegisterExternalExperiment(

tools/metrics/histograms/histograms.xml

@@ -71577,6 +71577,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Stability.Android.RendererCrash" enum="Boolean">
+  <owner>wnwen@chromium.org</owner>
+  <summary>
+    Counts renderer crashes including OOMs. Android only. Mirrors old stability
+    proto renderer crashes.
+  </summary>
+</histogram>
+
 <histogram name="Stability.BadMessageTerminated.Chrome"
     enum="BadMessageReasonChrome">
   <owner>nick@chromium.org</owner>