Remove ResourceFetcher::DeadResourceStatsRecorder

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 8e22a0ddff2f1deb6ed596cb942cbdb6dc95f08c..d9632a156e49875c1a1b4442278f2f1b1fbfa02a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -78652,6 +78652,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebCore.ResourceFetcher.HitCount">
+  <obsolete>
+    Deprecated April 2017.
+  </obsolete>
   <owner>clamy@chromium.org</owner>
   <summary>
     Number of dead resources found in the memory cache over the lifetime of the
@@ -78660,6 +78663,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebCore.ResourceFetcher.LoadCount">
+  <obsolete>
+    Deprecated April 2017.
+  </obsolete>
   <owner>clamy@chromium.org</owner>
   <summary>
     Number of resources that needed to be loaded by the ResourceFetcher over its
@@ -78690,6 +78696,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebCore.ResourceFetcher.RevalidateCount">
+  <obsolete>
+    Deprecated April 2017.
+  </obsolete>
   <owner>clamy@chromium.org</owner>
   <summary>
     Number of dead resources that needed to be revalidated by the