Implements logging in the new compact translate UI.

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 8b5dd5c804e344df612a0a8530a124c680d98038..52171583a1304ebe5e6d64680e482e9247a95017 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -75404,6 +75404,50 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Translate.Compact.Infobar.AlwaysTranslateLang">

[Ilya Sherman, 2017/05/11 00:04:10]

Optional nit: I'd name these histograms something like

"Translate.CompactUI.Language.AlwaysTranslate",
"Translate.CompactUI.Language.MoreLanguages",
etc.

(It's also fine to use "Translate.Compact.Infobar" if you think that name is
clearer -- though I'd kind of expect "Compact" to always be associated with
"Infobar", so I'd group it as "Translate.CompactInfobar".)

[ramyasharma, 2017/05/11 09:27:42]

Thanks for the suggestion Ilya. I have renamed these to
Translate.CompactInfobar.Language.

+  <owner>ramyasharma@google.com</owner>
+  <summary>
+    Records the hashcode of the source language when always translate this
+    language option is clicked in the menu.

[Ilya Sherman, 2017/05/11 00:04:09]

Seems like this histogram could use an enum associated with it, so that users
don't have to manually look up hashcode values.  Ditto for the other
hashcode-recording histograms.

[ramyasharma, 2017/05/11 09:27:42]

Thanks. Yes, I was able to reuse the enum CLD3LanguageCode. 

+  </summary>
+</histogram>
+
+<histogram name="Translate.Compact.Infobar.Event"
+    enum="TranslateCompactUIEvent">
+  <owner>ramyasharma@google.com</owner>
+  <summary>Various user actions performed in the translate infobar.</summary>
+</histogram>
+
+<histogram name="Translate.Compact.Infobar.MoreLanguagesTranslateLang">
+  <owner>ramyasharma@google.com</owner>
+  <summary>
+    Records the hashcode of the language clicked on the more languages menu.
+  </summary>
+</histogram>
+
+<histogram name="Translate.Compact.Infobar.NeverTranslateLang">
+  <owner>ramyasharma@google.com</owner>
+  <summary>
+    Records the hashcode of the source language when never translate this
+    language option is clicked in the menu.
+  </summary>
+</histogram>
+
+<histogram name="Translate.Compact.Infobar.PageNotInLang">
+  <owner>ramyasharma@google.com</owner>
+  <summary>
+    Records the hashcode of the language clicked on the menu to indicate the
+    page is not in the selected language.
+  </summary>
+</histogram>
+
+<histogram name="Translate.Compact.Infobar.TranslateLanguage">
+  <owner>ramyasharma@google.com</owner>
+  <summary>
+    Records the hashcode of the language clicked on the infobar.
+  </summary>
+</histogram>
+
 <histogram name="Translate.ContentLanguage" enum="TranslateLanguage">
   <owner>kenjibaheux@google.com</owner>
   <summary>