QUIC - Added histogram to track how often chrome sends/receives

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 8f9951027fcfab529a91aba50711e21071db6ccc..d8c28fbdace67997f22785aabd8508739f5e0ec3 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -17391,6 +17391,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.QuicSession.FlowControlBlockedFrame"
+    enum="QuicBlockedFrameType">
+  <owner>rtenneti@chromium.org</owner>
+  <summary>
+    Keeps track of number of flow-control BLOCKED frames either sent or
+    received.
+  </summary>
+</histogram>
+
 <histogram name="Net.QuicSession.HandshakeConfirmedTime" units="Milliseconds">
   <owner>rch@chromium.org</owner>
   <summary>
@@ -50554,6 +50563,11 @@ 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="QuicBlockedFrameType" type="int">
+  <int value="0" label="Received"/>
+  <int value="1" label="Sent"/>
+</enum>
+
 <enum name="QuicDiskCacheEntryState" type="int">
   <int value="0" label="Opened"/>
   <int value="1" label="Closed"/>