Bug 1093871 - Telemetry probe for number of items in reading list. r=rnewman

mobile/android/base/BrowserApp.java

@@ -1549,6 +1549,8 @@ public class BrowserApp extends GeckoApp
                     BrowserDB.getCount(getContentResolver(), "favicons"));
             Telemetry.HistogramAdd("FENNEC_THUMBNAILS_COUNT",
                     BrowserDB.getCount(getContentResolver(), "thumbnails"));
+            Telemetry.HistogramAdd("FENNEC_READING_LIST_COUNT",
+                    BrowserDB.getCount(getContentResolver(), "readinglist"));
             Telemetry.HistogramAdd("BROWSER_IS_USER_DEFAULT", (isDefaultBrowser(Intent.ACTION_VIEW) ? 1 : 0));
             if (Versions.feature16Plus) {
                 Telemetry.HistogramAdd("BROWSER_IS_ASSIST_DEFAULT", (isDefaultBrowser(Intent.ACTION_ASSIST) ? 1 : 0));

mobile/android/base/db/LocalBrowserDB.java

@@ -552,6 +552,9 @@ public class LocalBrowserDB {
         } else if ("favicons".equals(database)) {
             uri = mFaviconsUriWithProfile;
             columns = new String[] { Favicons._ID };
+        } else if ("readinglist".equals(database)) {
+            uri = mReadingListUriWithProfile;
+            columns = new String[] { ReadingListItems._ID };
         }
         if (uri != null) {
             final Cursor cursor = cr.query(uri, columns, constraint, null, null);

toolkit/components/telemetry/Histograms.json

@@ -3177,6 +3177,15 @@
     "extended_statistics_ok": true,
     "description": "Number of thumbnails stored in the browser DB"
   },
+  "FENNEC_READING_LIST_COUNT": {
+    "expires_in_version": "40",
+    "kind": "exponential",
+    "high": "1000",
+    "n_buckets": 10,
+    "cpp_guard": "ANDROID",
+    "extended_statistics_ok": true,
+    "description": "Number of reading list items stored in the browser DB"
+  },
   "PLACES_SORTED_BOOKMARKS_PERC": {
     "expires_in_version": "never",
     "kind": "linear",