Track age and score of snippets that are clicked (along with position).

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java
index 91ab35055fe4ddaef43b1da06da32de0a69b0c48..317008d7c4e2c2a61e315358ada3dfdfc93e8095 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java
@@ -39,6 +39,7 @@ public class SnippetArticleViewHolder extends NewTabPageViewHolder implements Vi
     private static final String TAG = "NtpSnippets";
     private static final String PUBLISHER_FORMAT_STRING = "%s - %s";
     private static final int FADE_IN_ANIMATION_TIME_MS = 300;
+    private static final int[] HISTOGRAM_FOR_POSITIONS = {0, 2, 4, 9};
 
     private final NewTabPageManager mNewTabPageManager;
     private final TextView mHeadlineTextView;
@@ -47,6 +48,8 @@ public class SnippetArticleViewHolder extends NewTabPageViewHolder implements Vi
     private final ImageView mThumbnailView;
 
     private FetchImageCallback mImageCallback;
+    private long mPublishTimestampMilliseconds;
+    private float mScore;
 
     public String mUrl;
     public int mPosition;
@@ -96,6 +99,22 @@ public class SnippetArticleViewHolder extends NewTabPageViewHolder implements Vi
         RecordHistogram.recordSparseSlowlyHistogram("NewTabPage.Snippets.CardClicked", mPosition);
         NewTabPageUma.recordSnippetAction(NewTabPageUma.SNIPPETS_ACTION_CLICKED);
         NewTabPageUma.recordAction(NewTabPageUma.ACTION_OPENED_SNIPPET);
+
+        // Track how the (approx.) position relates to age / score of the snippet that is clicked.
+        int ageInMinutes =
+                (int) ((System.currentTimeMillis() - mPublishTimestampMilliseconds) / 60000L);
+        recordAge("NewTabPage.Snippets.CardClickedAge", ageInMinutes);
+        recordScore("NewTabPage.Snippets.CardClickedScore", mScore);
+        int startPosition = 0;
+        for (int endPosition : HISTOGRAM_FOR_POSITIONS) {
+            if (mPosition >= startPosition && mPosition <= endPosition) {
+                String suffix = "_" + startPosition + "_" + endPosition;
+                recordAge("NewTabPage.Snippets.CardClickedAge" + suffix, ageInMinutes);
+                recordScore("NewTabPage.Snippets.CardClickedScore" + suffix, mScore);
+                break;
+            }
+            startPosition = endPosition + 1;
+        }
     }
 
     @Override
@@ -110,6 +129,8 @@ public class SnippetArticleViewHolder extends NewTabPageViewHolder implements Vi
         mArticleSnippetTextView.setText(item.mPreviewText);
         mUrl = item.mUrl;
         mPosition = item.mPosition;
+        mPublishTimestampMilliseconds = item.mTimestamp;
+        mScore = item.mScore;
 
         // If there's still a pending thumbnail fetch, cancel it.
         cancelImageFetch();
@@ -147,6 +168,20 @@ public class SnippetArticleViewHolder extends NewTabPageViewHolder implements Vi
         }
     }
 
+    private static void recordAge(String histogramName, int ageInMinutes) {
+        // Negative values (when the time of the device is set inappropriately) provide no value.
+        if (ageInMinutes >= 0) {
+            // If the max value below (72 hours) were to be changed, the histogram should be renamed
+            // since it will change the shape of buckets.
+            RecordHistogram.recordCustomCountHistogram(histogramName, ageInMinutes, 0, 72 * 60, 50);
+        }
+    }
+
+    private static void recordScore(String histogramName, float score) {
+        int recordedScore = Math.min((int) Math.ceil(score), 1000);
+        RecordHistogram.recordCount1000Histogram(histogramName, recordedScore);
+    }
+
     private void cancelImageFetch() {
         if (mImageCallback != null) {
             mImageCallback.cancel();