Also fixes Bug 988907 - Context menu and clicking-to-focus do not work in empty space above/below newtab grid
Cover up the sites that become position: absolute (and escape the flow for overflow: hidden) with an explicit background color for the bottom margin.
Always Grid_init before "load", defer size calculation to "load", and only wait for links cache for site rendering. Clean up timers triggered from previous tests to avoid unexpected updates.
--HG--
extra : rebase_source : aba79dc12fd3660c50d8004197a6b2f5a23419cb
Also fixes bug 976638 by moving controls.png to the shared directory.
Add an always visible sponsored icon for tiles that are type=sponsored. Also add ignorehover to the cell to prevent styling when pointing at the sponsored icon that happens to be a child of the cell.
Remove newtab-rows and convert the grid to wrap/overflow tiles as necessary by setting the appropriate width and heights. Compute grid dimensions on load/preload and adjust for resizes.
