Add viewed download files metrics on Android.

This CL adds the initial count for download files.

The metric is recorded when Android code loaded the history database
records.

Bug: 817220
Change-Id: I571ecbca2aacc3a2be863cdf36310b32569fabe1
Reviewed-on: https://chromium-review.googlesource.com/941519
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540328}

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java

@@ -849,6 +849,17 @@ public static ColorStateList getIconForegroundColorList(Context context) {
                 context.getResources(), R.color.white_mode_tint);
     }
 
+    /**
+     * Return if a download item is already viewed by the user. Will return false if the last
+     * access time is not available.
+     * @param item The download item.
+     * @return true if the item is viewed by the user.
+     */
+    public static boolean isDownloadViewed(DownloadItem item) {
+        if (item == null || item.getDownloadInfo() == null) return false;
+        return item.getDownloadInfo().getLastAccessTime() != 0;
+    }
+
     private static boolean isMimeTypeVideo(String mimeType) {
         if (TextUtils.isEmpty(mimeType)) return false;
 

chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java

@@ -21,6 +21,7 @@
 import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.download.DownloadItem;
 import org.chromium.chrome.browser.download.DownloadSharedPreferenceHelper;
+import org.chromium.chrome.browser.download.DownloadUtils;
 import org.chromium.chrome.browser.download.ui.BackendProvider.DownloadDelegate;
 import org.chromium.chrome.browser.download.ui.DownloadHistoryItemWrapper.DownloadItemWrapper;
 import org.chromium.chrome.browser.download.ui.DownloadHistoryItemWrapper.OfflineItemWrapper;
@@ -272,12 +273,16 @@ public void onAllDownloadsRetrieved(List<DownloadItem> result, boolean isOffTheR
         assert list.size() == 0;
 
         int[] itemCounts = new int[DownloadFilter.FILTER_BOUNDARY];
+        int[] viewedItemCounts = new int[DownloadFilter.FILTER_BOUNDARY];
 
         for (DownloadItem item : result) {
             DownloadItemWrapper wrapper = createDownloadItemWrapper(item);
             if (addDownloadHistoryItemWrapper(wrapper)
                     && wrapper.isVisibleToUser(DownloadFilter.FILTER_ALL)) {
                 itemCounts[wrapper.getFilterType()]++;
+
+                if (DownloadUtils.isDownloadViewed(wrapper.getItem()))
+                    viewedItemCounts[wrapper.getFilterType()]++;
                 if (!isOffTheRecord && wrapper.getFilterType() == DownloadFilter.FILTER_OTHER) {
                     RecordHistogram.recordEnumeratedHistogram(
                             "Android.DownloadManager.OtherExtensions.InitialCount",
@@ -287,7 +292,7 @@ public void onAllDownloadsRetrieved(List<DownloadItem> result, boolean isOffTheR
             }
         }
 
-        if (!isOffTheRecord) recordDownloadCountHistograms(itemCounts);
+        if (!isOffTheRecord) recordDownloadCountHistograms(itemCounts, viewedItemCounts);
 
         list.setIsInitialized();
         onItemsRetrieved(isOffTheRecord
@@ -732,7 +737,7 @@ private DownloadItemWrapper createDownloadItemWrapper(DownloadItem item) {
         return new DownloadItemWrapper(item, mBackendProvider, mParentComponent);
     }
 
-    private void recordDownloadCountHistograms(int[] itemCounts) {
+    private void recordDownloadCountHistograms(int[] itemCounts, int[] viewedItemCounts) {
         RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Audio",
                 itemCounts[DownloadFilter.FILTER_AUDIO]);
         RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Document",
@@ -743,6 +748,17 @@ private void recordDownloadCountHistograms(int[] itemCounts) {
                 itemCounts[DownloadFilter.FILTER_OTHER]);
         RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Video",
                 itemCounts[DownloadFilter.FILTER_VIDEO]);
+
+        RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Viewed.Audio",
+                viewedItemCounts[DownloadFilter.FILTER_AUDIO]);
+        RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Viewed.Document",
+                viewedItemCounts[DownloadFilter.FILTER_DOCUMENT]);
+        RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Viewed.Image",
+                viewedItemCounts[DownloadFilter.FILTER_IMAGE]);
+        RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Viewed.Other",
+                viewedItemCounts[DownloadFilter.FILTER_OTHER]);
+        RecordHistogram.recordCountHistogram("Android.DownloadManager.InitialCount.Viewed.Video",
+                viewedItemCounts[DownloadFilter.FILTER_VIDEO]);
     }
 
     private void recordTotalDownloadCountHistogram() {

tools/metrics/histograms/histograms.xml

@@ -967,6 +967,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Android.DownloadManager.InitialCount.Viewed">
+  <owner>xingliu@chromium.org</owner>
+  <summary>
+    The number of non-incognito download items displayed that are already viewed
+    by the user at any time, recorded when the download UI is initialized.
+  </summary>
+</histogram>
+
 <histogram name="Android.DownloadManager.Item.OpenFailed"
     enum="AndroidDownloadFilterType">
   <owner>dfalcantara@chromium.org</owner>
@@ -103427,6 +103435,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <suffix name="Total"/>
   <suffix name="Video"/>
   <affected-histogram name="Android.DownloadManager.InitialCount"/>
+  <affected-histogram name="Android.DownloadManager.InitialCount.Viewed"/>
 </histogram_suffixes>
 
 <histogram_suffixes name="AndroidGATTEvents" separator=".">