Add two new WebSocket histograms to track adoption of the permessage-deflate extension.

tools/metrics/histograms/histograms.xml

 <!--
 Copyright 2013 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <!--
 This file is used to generate a comprehensive list of Chrome histograms along
 with a detailed description for each histogram.
 
@@ skipping 8791 matching lines @@
   </summary>
 </histogram>
 
 <histogram name="WebCore.V8DOMWindowShell.createContext.MainWorld"
     units="milliseconds">
   <summary>
     Duration of time taken to create a V8 Context for the main world.
   </summary>
 </histogram>
 
+<histogram name="WebCore.WebSocket.HandshakeResult"
+    enum="WebSocketHandshakeResult">
+  <summary>
+    Count the number of WebSocket handshake for each result. Use this histogram
+    as a baseline for investigating feature usage counters.
+  </summary>
+</histogram>
+
+<histogram name="WebCore.WebSocket.PerMessageDeflateContextTakeOverMode"
+    enum="WebSocketPerMessageDeflateContextTakeOverMode">
+  <summary>
+    Count the number of WebSockets that accepted permessage-deflate extension
+    for each context take over mode.
+  </summary>
+</histogram>
+
 <histogram name="WebCore.XHR.send.ArrayBufferOrView"
     enum="XMLHttpRequestSendArrayBufferOrView">
   <summary>
     Count the number of XHR.send() calls for each argument type to see when we
     can deprecate the ArrayBuffer type support.
   </summary>
 </histogram>
 
 <histogram name="WebFont.LoadTime.0.Under10KB" units="milliseconds">
   <summary>
@@ skipping 4343 matching lines @@
   <int value="4" label="Set up Wallet"/>
   <int value="5" label="Accept ToS"/>
   <int value="6" label="Update expiration date"/>
   <int value="7" label="Upgrade min address"/>
   <int value="8" label="Choose another instrument or address"/>
   <int value="9" label="Verify CVV"/>
   <int value="10" label="Invalid form field"/>
   <int value="11" label="Require phone number"/>
 </enum>
 
+<enum name="WebSocketHandshakeResult" type="int">
+  <int value="0" label="Incomplete"/>
+  <int value="1" label="Normal"/>
+  <int value="2" label="Failed"/>
+  <int value="3" label="Connected"/>
+</enum>
+
+<enum name="WebSocketPerMessageDeflateContextTakeOverMode" type="int">
+  <int value="0" label="DoNotTakeOverContext"/>
+  <int value="1" label="TakeOverContext"/>
+</enum>
+
 <enum name="WiFiReasonCode" type="int">
   <int value="0" label="kReasonReserved0"/>
   <int value="1" label="kReasonCodeUnspecified"/>
   <int value="2" label="kReasonCodePreviousAuthenticationInvalid"/>
   <int value="3" label="kReasonCodeSenderHasLeft"/>
   <int value="4" label="kReasonCodeInactivity"/>
   <int value="5" label="kReasonCodeTooManySTAs"/>
   <int value="6" label="kReasonCodeNonAuthenticated"/>
   <int value="7" label="kReasonCodeNonAssociated"/>
   <int value="8" label="kReasonCodeDisassociatedHasLeft"/>
@@ skipping 1490 matching lines @@
 <fieldtrial name="SSLResumption">
   <group name="Resume_Handshake" label="Session Resumption"/>
   <group name="Full_Handshake" label="Full"/>
   <affected-histogram name="Net.SSL_Connection_Latency"/>
   <affected-histogram name="Net.SSL_Connection_Latency_Google"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>