Server push cancellation: add metrics collection for

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 1b79ca737d73b284ba3c4f9ff1e2fa782e539d38..b2c02faf04b9761131d6673986d944c41d09bec8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -33254,6 +33254,20 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Socket connected status in SpdySession::CreateStream.</summary>
 </histogram>
 
+<histogram name="Net.SpdySession.PushedAndUnclaimedBytes" units="count">
+  <owner>zhongyi@chromium.org</owner>
+  <summary>
+    The number of bytes that is pushed but not used when the session is closed.
+  </summary>
+</histogram>
+
+<histogram name="Net.SpdySession.PushedBytes" units="count">
+  <owner>zhongyi@chromium.org</owner>
+  <summary>
+    The number of bytes that is pushed when the session is closed.
+  </summary>
+</histogram>
+
 <histogram name="Net.SpdySessionErrorDetails" enum="SpdyProtocolErrorDetails"
     units="count">
   <obsolete>