QUIC - track the open and close states of disk cache entries of

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 88857bae30674204bf4649537f327720afdeffa1..1a5bc02471f4988e089d4a8f4d27dd31d9a59c97 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -16836,6 +16836,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.QuicDiskCache.EntryState" enum="QuicDiskCacheEntryState">
+  <owner>rtenneti@chromium.org</owner>
+  <summary>
+    Tracks the opening and closing of disk cache entries. Recorded each time a
+    disk cache entry is either opened or closed.
+  </summary>
+</histogram>
+
 <histogram name="Net.QuicEphemeralPortsSuggested">
   <owner>rch@chromium.org</owner>
   <summary>The number of ports suggested per server.</summary>
@@ -49710,6 +49718,11 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="7" label="Address and port match: IPv6 IPv6"/>
 </enum>
 
+<enum name="QuicDiskCacheEntryState" type="int">
+  <int value="0" label="Opened"/>
+  <int value="1" label="Closed"/>
+</enum>
+
 <enum name="QuicErrorCodes" type="int">
   <int value="0" label="NO_ERROR"/>
   <int value="1" label="INTERNAL_ERROR"/>