Deprecate several obsolete QUIC histograms.

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 4f1ec4167292e4484b030fa076457f8e5f1b56f0..79311c02df3e6a5f310beebf2cceb348449a48f0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -35989,6 +35989,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.QuicDiskCache.APICall" enum="QuicDiskCacheAPICall">
+  <obsolete>
+    Deprecated as of 4/15/2017.
+  </obsolete>
   <owner>rtenneti@chromium.org</owner>
   <summary>
     Tracks number of times data read/parse/write API calls of QuicServerInfo to
@@ -36142,6 +36145,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.QuicServerInfo.DiskCacheLoadTime" units="ms">
+  <obsolete>
+    Deprecated as of 4/15/2017.
+  </obsolete>
   <owner>rtenneti@chromium.org</owner>
   <summary>Time spent to load QUIC server information from disk cache.</summary>
 </histogram>
@@ -36172,6 +36178,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="Net.QuicServerInfo.ExpectConfigMissingFromDiskCache"
     enum="BooleanMissingFromDiskCache">
+  <obsolete>
+    Deprecated as of 4/15/2017.
+  </obsolete>
   <owner>rtenneti@chromium.org</owner>
   <summary>
     The number of times AlternateProtocolMap supports QUIC, but there is no QUIC
@@ -36192,6 +36201,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.QuicServerInfo.WaitForDataReadyToRtt" units="%">
+  <obsolete>
+    Deprecated as of 4/15/2017.
+  </obsolete>
   <owner>rtenneti@chromium.org</owner>
   <summary>
     The ratio of the time spent waiting to load QUIC server information from