Relax background tiling snapping

The previous fix for backgrounds repeating when they shouldn't
was too restrictive and still allowed backgrounds to repeat at
some zoom levels. Switch from "<" to "<=" to snap the remaining
cases.

Bug: 1085801
Change-Id: Iedf79fa9980ade753b4ca108d7462b282652eeeb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2222540
Commit-Queue: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Auto-Submit: Stephen Chenney <schenney@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#773223}

third_party/blink/renderer/core/paint/box_painter_base.cc

@@ -472,10 +472,10 @@ void DrawTiledBackground(GraphicsContext& context,
   //
   // So detect when we do not want to repeat and set the scale to round the
   // values in that dimension.
-  if (fabs(tile_size.Width() - snapped_paint_rect.Width()) < 0.5) {
+  if (fabs(tile_size.Width() - snapped_paint_rect.Width()) <= 0.5) {
     scale.SetWidth(snapped_paint_rect.Width() / intrinsic_tile_size.Width());
   }
-  if (fabs(tile_size.Height() - snapped_paint_rect.Height()) < 0.5) {
+  if (fabs(tile_size.Height() - snapped_paint_rect.Height()) <= 0.5) {
     scale.SetHeight(snapped_paint_rect.Height() / intrinsic_tile_size.Height());
   }