Added and replaced some UMAs

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 085d0896c0e875c0b83dbba42992efe66b69da83..2c373999886cdbaf8b3f5b228f21abdc4a90d2a0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -8647,6 +8647,28 @@ other types of suffix sets.
   <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