[TTS] Add UMA metric for translation condition

Adds a new UMA metric to track whether or not translation conditions are
met for each search term.

Bug: 
Change-Id: Ib240408c8df1862f55f592f5413599a730209fd1
Reviewed-on: https://chromium-review.googlesource.com/679447
Commit-Queue: Mehran Mahmoudi <mahmoudi@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504248}

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchTranslateController.java

@@ -56,6 +56,9 @@ public class ContextualSearchTranslateController  {
         // Log that conditions were right for translation, even though it may be disabled
         // for an experiment so we can compare with the counter factual data.
         ContextualSearchUma.logTranslateOnebox(doForceTranslate);
+
+        // Log whether or not translate conditions are met
+        ContextualSearchUma.logTranslateCondition(doForceTranslate);
     }
 
     /**

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchUma.java

@@ -1216,6 +1216,15 @@ public class ContextualSearchUma {
                 "Search.ContextualSearchShouldTranslate", code, FORCE_TRANSLATE_BOUNDARY);
     }
 
+    /**
+     * Logs that whether or not the conditions are met to perform a translation.
+     * @param isConditionMet Whether the translation conditions were met.
+     */
+    public static void logTranslateCondition(boolean isConditionMet) {
+        RecordHistogram.recordBooleanHistogram(
+                "Search.ContextualSearchTranslateCondition", isConditionMet);
+    }
+
     /**
      * Logs whether Contextual Cards data was shown. Should be logged on tap if Contextual
      * Cards integration is enabled.

tools/metrics/histograms/histograms.xml

@@ -72334,6 +72334,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Search.ContextualSearchTranslateCondition" enum="Boolean">
+  <owner>donnd@chromium.org</owner>
+  <owner>mahmoudi@chromium.org</owner>
+  <owner>twellington@chromium.org</owner>
+  <summary>
+        For each contextual search that is triggered by tap, records whether the
+    translation conditions are met. Implemented for Android.
+  </summary>
+</histogram>
+
 <histogram name="Search.DefaultSearchChangeOrigin"
     enum="DefaultSearchChangeOrigin">
   <owner>mathp@chromium.org</owner>