Replace SSLProtocolNegotiation histogram with SSLNegotiatedAlpnProtocol.

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 acd066011acf3affe6c1b09c97b61041d8ab2ed0..796a71212320e5ce5b2c474c189301776576606b 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -32537,6 +32537,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Time to complete a speculative certificate verification.</summary>
 </histogram>
 
+<histogram name="Net.SSLNegotiatedAlpnProtocol" enum="NegotiatedAlpnProtocol">
+  <owner>bnc@chromium.org</owner>
+  <summary>
+    For each TLS handshake, whether ALPN was negotiated; and if so, the
+    negotiated protocol.
+  </summary>
+</histogram>
+
 <histogram name="Net.SSLProtocolErrorCipher" enum="SSLCipherSuite">
   <obsolete>
     Removed in March 2016.
@@ -32563,6 +32571,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.SSLProtocolNegotiation" enum="SSLProtocolNegotiation">
+  <obsolete>
+    Superseded by Net.SSLNegotiatedAlpnProtocol in 2016 August.
+  </obsolete>
   <owner>bnc@chromium.org</owner>
   <summary>
     TLS extension used to negotiate protocol (ALPN or NPN); in case of NPN,
@@ -87009,6 +87020,12 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="5" label="Cross-origin subframe vibrate, with user gesture"/>
 </enum>
 
+<enum name="NegotiatedAlpnProtocol" type="int">
+  <int value="0" label="ALPN not used"/>
+  <int value="1" label="HTTP/1.1 negotiated via ALPN"/>
+  <int value="2" label="HTTP/2 negotiated via ALPN"/>
+</enum>
+
 <enum name="NetCacheState" type="int">
   <int value="0" label="FROM_CACHE"/>
   <int value="1" label="STILL_VALID"/>