Update StatsLogManager to support ranking related events.

Change-Id: I238f00a782a620f704005d37c8972b5e25610c75

src/com/android/launcher3/logging/StatsLogManager.java

@@ -141,6 +141,25 @@ public class StatsLogManager implements ResourceBasedOverride {
         }
     }
 
+    /**
+     * Launcher specific ranking related events.
+     */
+    public enum LauncherRankingEvent implements EventEnum {
+
+        UNKNOWN(0);
+        // ADD MORE
+
+        private final int mId;
+
+        LauncherRankingEvent(int id) {
+            mId = id;
+        }
+
+        public int getId() {
+            return mId;
+        }
+    }
+
     protected LogStateProvider mStateProvider;
 
     /**
@@ -181,6 +200,19 @@ public class StatsLogManager implements ResourceBasedOverride {
     public void log(EventEnum event, InstanceId instanceId, @Nullable ItemInfo itemInfo) {
     }
 
+    /**
+     * Log an event with ranked-choice information along with package. Does nothing if event.getId()
+     * <= 0.
+     *
+     * @param rankingEvent an enum implementing UiEventEnum interface.
+     * @param instanceId An identifier obtained from an InstanceIdSequence.
+     * @param packageName the package name of the relevant app, if known (null otherwise).
+     * @param position the position picked.
+     */
+    public void log(EventEnum rankingEvent, InstanceId instanceId, @Nullable String packageName,
+            int position) {
+    }
+
     /**
      * Logs an event and accompanying {@link LauncherState}s. If either of the state refers
      * to workspace state, then use pageIndex to pass in index of workspace.