In progress at: https://chromium-review.googlesource.com/c/chromium/src/+/866790

hugo@ I attached a test case. Test step is
1. Focus to bottom most element.
2. Hit up arrow key.

Expected result:
focus should move to top most element.

Actual result:
focus not move anywhere.

Deleted: container5.html 856 bytes

container5.html 856 bytes View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af

commit b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af
Author: Hugo Holgersson <hugoh@vewd.com>
Date: Thu Jan 18 16:56:24 2018

Snav: Search containers that reached their scroll limit

Problem:
A fully scrolled container might still have nearby
focusables. Before this CL, those were ignored.

Solution:
This adds a new helper IsScrollableAreaOrDocument() that
we can use in ScrollableEnclosingBoxOrParentFrameOf()
to find a node's "container":

Q: What is a "container"?
A: A node's _container_ is its enclosing scrollable area
   (= its first scrollable ancestor) or its document
   (possibly unscrollable).

In other words, we don't need a direction to determine
a node's container. This is a simplification that's
needed to fix  bug 770103 .

Bug: 770147,  770103 
Change-Id: I439d532631e9d424e40e801873ef330cd15ffe7f
Reviewed-on: https://chromium-review.googlesource.com/866790
Commit-Queue: Hugo Holgersson <hugoh@vewd.com>
Reviewed-by: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530169}
[add] https://crrev.com/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af/third_party/WebKit/LayoutTests/fast/spatial-navigation/snav-stay-in-overflow-div-expected.txt
[add] https://crrev.com/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af/third_party/WebKit/LayoutTests/fast/spatial-navigation/snav-stay-in-overflow-div.html
[modify] https://crrev.com/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af/third_party/WebKit/Source/core/page/FocusController.cpp
[modify] https://crrev.com/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af/third_party/WebKit/Source/core/page/SpatialNavigation.cpp
[modify] https://crrev.com/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af/third_party/WebKit/Source/core/page/SpatialNavigation.h
[modify] https://crrev.com/b1eaec2e1fe9eb6bc37b6a43a574a081d914b2af/third_party/WebKit/Source/core/page/SpatialNavigationTest.cpp