[key event focus] DPAD navigates to the nearest item on next/previous page

b/19381790
b/16351792

TL;DR;; Previously, when RIGHT is handled on the right most column of the
current page or when LEFT is handled on the left most column, the next
icon of focus is next page 'first' icon or the previous page 'last icon'.
With this change, the row information is preserved when trying to locate
an icon to give focus in the next/previous page.

Next CL: long awaited unit tests that capture corner cases for different
orientation/ device configuration.

Change-Id: I5278bed45275b3e4cb39fb698df35f90bb45a415