Added and replaced some UMAs

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 8629 matching lines @@
   <summary>
     The time from injecting scripts for Chrome Translate to the finishing loads
     of all depending libraries.
   </summary>
 </histogram>
 
 <histogram name="Translate.TimeToTranslate" units="milliseconds">
   <summary>The time from starting translation to the completion.</summary>
 </histogram>
 
+<histogram name="Translate.UnavailableLanguage" enum="LanguageCode">
+  <summary>
+    Logs the source language when a Translate infobar is shown with an
+    unsupported source language.  There are two cases when this can occur:  The
+    first is when the user selects automatic language detection and the detected
+    language is unsupported by the translation server because it is too minor.
+    The other is when the infobar UI is broken and the user can directly choose
+    the language. The former can happen because the language set of Chrome and
+    that of the translation server may differ.
+  </summary>
+</histogram>
+
+<histogram name="Translate.UnsupportedLanguageAtInitiation" enum="LanguageCode">
+  <summary>
+    Logs an unsupported source language detected during initiation of the
+    Translate feature.  This is reported when the language detector successfully
+    detects the language of the webpage, but the language is not supported by
+    the translation server because it is too minor.  This metric allows us to
+    assess how important the unsupported language is for Google translate.
+  </summary>
+</histogram>
+
 <histogram name="Translate.UserActionDuration" units="milliseconds">
   <summary>
     The time from a page content language being determined to user requesting
     Chrome Translate.
   </summary>
 </histogram>
 
 <histogram name="UMA.Perf.GetData" enum="GetPerfDataOutcome">
   <summary>
     A count of successes and various failure modes related to collecting and
@@ skipping 6715 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>