Focus handling null pointer exception during monkey tests.

- Also fix a bug where the focus is not navigating to the next page when there
isn't an icon within +45 and -45 range of the origin.

b/20294717

Change-Id: I16dac5c6a0463fbc9f56a447abedad18abadde98

src/com/android/launcher3/PagedView.java

@@ -475,13 +475,14 @@ public abstract class PagedView extends ViewGroup implements ViewGroup.OnHierarc
 
     /**
      * Returns the index of the currently displayed page.
-     *
-     * @return The index of the currently displayed page.
      */
     int getCurrentPage() {
         return mCurrentPage;
     }
 
+    /**
+     * Returns the index of page to be shown immediately afterwards.
+     */
     int getNextPage() {
         return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
     }