Add hidden API to retrieve ActivityInfo

This API will be used by Exo to determine whether the Activity supports
only portrait or landscape.

Bug: 172927807
Test: make
Change-Id: I290b051b645e2bfb9eff9b615b44a08fe439ceca

core/java/android/content/pm/LauncherActivityInfo.java

@@ -128,6 +128,16 @@ public class LauncherActivityInfo {
         return mInternal.getActivityInfo().flags;
     }
 
+    /**
+     * Returns the ActivityInfo of the activity.
+     *
+     * @return Activity Info
+     * @hide
+     */
+    public ActivityInfo getActivityInfo() {
+        return mInternal.getActivityInfo();
+    }
+
     /**
      * Returns the application info for the appliction this activity belongs to.
      * @return