Remove SHA-1 metrics

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 d09861039e964d030a1eafd59863a6318e26a23c..5c2bc20e80d8c887d0ba0dd7b6a1f024213dd4d0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -34645,6 +34645,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.Certificate.SHA1.MainFrame" enum="SHA1Status">
+  <obsolete>
+    Deprecated 06/2017 as SHA-1 was successfully disabled in 01/2017.
+  </obsolete>
   <owner>rsleevi@chromium.org</owner>
   <summary>
     Whether or not SHA-1 was present in a resource fetched for the main frame,
@@ -34653,6 +34656,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.Certificate.SHA1.Subresource" enum="SHA1Status">
+  <obsolete>
+    Deprecated 06/2017 as SHA-1 was successfully disabled in 01/2017.
+  </obsolete>
   <owner>rsleevi@chromium.org</owner>
   <summary>
     Whether or not SHA-1 was present in a subresource fetch, and if so, what its