Introduce new SPDY Version UMA histogram.

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 96a571ee1b69bd6287b396cdd7b79b8fc4abaef4..e7f4e34cbd86ac0d2d3e3c5512cf96b2a2161ff8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -17367,12 +17367,24 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 </histogram>
 
 <histogram name="Net.SpdyVersion" enum="ProtocolVersion">
+  <obsolete>
+    Deprecated on 2014-09-11, because the uploaded values were changing as
+    protocols were removed, therefore statistics couldn't be combined accross
+    different builds.  Replaced by Net.SpdyVersion2.
+  </obsolete>
   <owner>rch@chromium.org</owner>
   <summary>
     The SPDY protocol version that is used to talk to SPDY servers.
   </summary>
 </histogram>
 
+<histogram name="Net.SpdyVersion2" enum="SpdyProtocolVersion">
+  <owner>bnc@chromium.org</owner>
+  <summary>
+    The SPDY protocol version that is used to talk to SPDY servers.
+  </summary>
+</histogram>
+
 <histogram name="Net.SSL_CipherSuite" enum="SSLCipherSuite">
   <owner>agl@chromium.org</owner>
   <owner>rsleevi@chromium.org</owner>
@@ -48493,10 +48505,10 @@ To add a new entry, add it with any value and run test to compute valid value.
 <enum name="ProtocolVersion" type="int">
   <int value="0" label="UNKNOWN"/>
   <int value="1" label="HTTP 1.1"/>
-  <int value="2" label="SPDY 1.0"/>
-  <int value="3" label="SPDY 2.0"/>
-  <int value="4" label="SPDY 2.1"/>
-  <int value="5" label="SPDY 3.0"/>
+  <int value="2" label="SPDY 2.0"/>
+  <int value="3" label="SPDY 3.0"/>
+  <int value="4" label="SPDY 3.1"/>
+  <int value="5" label="SPDY 4.0"/>
 </enum>
 
 <enum name="ProvisionalSaveFailure" type="int">
@@ -49878,6 +49890,14 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="34" label="Peer exhibiting suspect behavior."/>
 </enum>
 
+<enum name="SpdyProtocolVersion" type="int">
+  <int value="0" label="UNKNOWN"/>
+  <int value="1" label="SPDY 2.0"/>
+  <int value="2" label="SPDY 3.0"/>
+  <int value="3" label="SPDY 3.1"/>
+  <int value="4" label="HTTP/2 draft-14"/>
+</enum>
+
 <enum name="SpdySessionGet" type="int">
   <int value="0" label="created new"/>
   <int value="1" label="found existing"/>