Snav: Remove some irrelevant "overlap" logic

DeflateIfOverlapped() was introduced in SpatNav's
very first WebKit commit [1], seemingly, to get some
support for certain overlapping elements. It seems
like we no longer need it...

Since crrev.com/c/1605696, SpatNav better supports
generic overlapping rects.

The spec [2] that formalizes Chromium's SpatNav
implementation never included it either.

[1] https://trac.webkit.org/browser/webkit/trunk/
      WebCore/page/SpatialNavigation.cpp?rev=55543
[2] https://drafts.csswg.org/css-nav-1/

Bug: 770147, 1000578
Change-Id: I498ccdb5032d97c89a5c015c893a2e5f08edd1f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1949785
Commit-Queue: Hugo Holgersson <hholgersson@fb.com>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#721485}

third_party/blink/renderer/core/page/spatial_navigation.cc

@@ -56,8 +56,6 @@ constexpr double kMinDistance = std::numeric_limits<int>::lowest();
 
 constexpr int kFudgeFactor = 2;
 
-static void DeflateIfOverlapped(PhysicalRect&, PhysicalRect&);
-
 FocusCandidate::FocusCandidate(Node* node, SpatialNavigationDirection direction)
     : visible_node(nullptr), focusable_node(nullptr), is_offscreen(true) {
   DCHECK(node);
@@ -313,22 +311,6 @@ bool ScrollInDirection(Node* container, SpatialNavigationDirection direction) {
   return true;
 }
 
-static void DeflateIfOverlapped(PhysicalRect& a, PhysicalRect& b) {
-  if (!a.Intersects(b) || a.Contains(b) || b.Contains(a))
-    return;
-
-  LayoutUnit deflate_factor = LayoutUnit(-kFudgeFactor);
-
-  // Avoid negative width or height values.
-  if ((a.Width() + 2 * deflate_factor > 0) &&
-      (a.Height() + 2 * deflate_factor > 0))
-    a.Inflate(deflate_factor);
-
-  if ((b.Width() + 2 * deflate_factor > 0) &&
-      (b.Height() + 2 * deflate_factor > 0))
-    b.Inflate(deflate_factor);
-}
-
 bool IsScrollableNode(const Node* node) {
   if (!node)
     return false;
@@ -630,7 +612,6 @@ double ComputeDistanceDataForNode(SpatialNavigationDirection direction,
   } else if (!IsRectInDirection(direction, current_rect, node_rect)) {
     return kMaxDistance;
   } else {
-    DeflateIfOverlapped(current_rect, node_rect);
     PhysicalRect intersection_rect = Intersection(current_rect, node_rect);
     overlap =
         (intersection_rect.Width() * intersection_rect.Height()).ToDouble();