Set Token-Binding HTTP header

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 fb23e7c6c99fea41c095ec37de390db4a1d34c4a..4b20594029b51969fe11bf2f3e1c8f7d34411aaa 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -27302,6 +27302,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Net.TokenBinding.Support" enum="TokenBinding.Support">
+  <owner>nharper@chromium.org</owner>
+  <summary>
+    Count of number of secure HTTP requests broken down by support for Token
+    Binding, indicating if Token Binding was negotiated and supported by both
+    client and server, or why it wasn't if not.
+  </summary>
+</histogram>
+
 <histogram name="Net.Transaction_Bandwidth" units="KB/s">
   <obsolete>
     Discontinued as of 4/12/09
@@ -79084,6 +79093,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1" label="Renegotiation patched"/>
 </enum>
 
+<enum name="TokenBinding.Support" type="int">
+  <int value="0" label="DISABLED"/>
+  <int value="1" label="CLIENT_ONLY"/>
+  <int value="2" label="CLIENT_AND_SERVER"/>
+  <int value="3" label="CLIENT_NO_CHANNEL_ID_SERVICE"/>
+</enum>
+
 <enum name="TouchEventsState" type="int">
   <int value="0" label="Enabled"/>
   <int value="1" label="Automatic - enabled"/>