Adds translate infobar impression in the old Translate UI on Android

This is added so that we can compare the impressions in old UI and
the new one.

BUG=720231

Review-Url: https://codereview.chromium.org/2897233002
Cr-Commit-Position: refs/heads/master@{#474961}

chrome/android/java/src/org/chromium/chrome/browser/infobar/TranslateInfoBar.java

@@ -14,6 +14,7 @@ import android.text.style.ClickableSpan;
 import android.view.View;
 
 import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.R;
 import org.chromium.ui.base.DeviceFormFactor;
 
@@ -42,6 +43,8 @@ public class TranslateInfoBar extends InfoBar implements SubPanelListener {
     private TranslateSubPanel mSubPanel;
     private final boolean mShouldShowNeverBar;
 
+    private static final String INFOBAR_IMPRESSION_HISTOGRAM = "Translate.InfobarShown";
+
     @CalledByNative
     private static InfoBar show(int translateBarType, String sourceLanguageCode,
             String targetLanguageCode, boolean alwaysTranslate, boolean showNeverInfobar,
@@ -173,6 +176,16 @@ public class TranslateInfoBar extends InfoBar implements SubPanelListener {
 
     @Override
     public void createContent(InfoBarLayout layout) {
+        // Log infobar impression only when the infobar shown is either in step: before translate
+        // or in step: translating and always enabled is true. This is to remove duplicate
+        // impressions.
+        int infoBarType = getInfoBarType();
+        if (infoBarType == BEFORE_TRANSLATE_INFOBAR
+                || (mOptions.alwaysTranslateLanguageState()
+                           && infoBarType == TRANSLATING_INFOBAR)) {
+            RecordHistogram.recordBooleanHistogram(INFOBAR_IMPRESSION_HISTOGRAM, true);
+        }
+
         if (mOptionsPanelViewType == NO_PANEL) {
             mSubPanel = null;
         } else {

tools/metrics/histograms/histograms.xml

@@ -77039,6 +77039,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Translate.InfobarShown" enum="BooleanHit">
+  <owner>ramyasharma@google.com</owner>
+  <summary>
+    The number of times the translate infobar was shown in the UI on Android.
+    Only true is recorded.
+  </summary>
+</histogram>
+
 <histogram name="Translate.InitiationStatus" enum="TranslateInitiationStatus">
   <obsolete>
     Deprecated as of 11/2013, and replaced by Translate.InitiationStatus.v2.