Fix NPE when mRecentsView is null

The NPE was in an unused variable, so also address the TODO to use it as log rank.

Test: wwdebug, wwlogcat, quickswitch and check rank field
Fixes: 218216440
Change-Id: I173ae607e9f73e58880c0fb1b6e8f2352469816f
diff --git a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
index e218db1..2cb7100 100644
--- a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
+++ b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
@@ -1198,10 +1198,10 @@
             // We probably never received an animation controller, skip logging.
             return;
         }
-        int pageIndex = endTarget == LAST_TASK
+        int pageIndex = endTarget == LAST_TASK || mRecentsView == null
                 ? LOG_NO_OP_PAGE_INDEX
                 : mRecentsView.getNextPage();
-        // TODO: set correct container using the pageIndex
+        logger.withRank(pageIndex);
         logger.log(event);
     }