tree 0c88e95a58a5b108b72711b56ff2a4ceed9c665d
parent d89f2fcb5a3848ab24801b1f3fcc144b785869fa
author Kent Tamura <tkent@chromium.org> 1572326058 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1572326621 -0400

Fix default tabIndex IDL attribute values

We follow https://html.spec.whatwg.org/C/#dom-tabindex by this CL.
The old behavior of default tabIndex was something like "Returns 0
if the element is focusable, -1 otherwise". But it didn't match to
the HTML standard, and was not interoperable.

Since this CL, some elements return -1 if "tabindex" attribute is
missing or invalid regardless of their focusability.

Implementation:
Node::tabIndex() is not a virtual function any longer. We have only
Element::tabIndex(), and it calls virtual DefaultTabIndex() if
"tabindex" attribute is missing or invalid.

DefaultTabIndex() for elements listed in the specification returns 0.
Otherwise, it returns -1.
 - HTMLAnchorElement affects <a> and <area>
 - HTMLFormControlElementWithState affects <input>, <select>, and
   <textarea>.
 - HTMLFrameElementBase affects <frame> and <iframe>

Blink can't use Element::tabIndex() for the purpose of focusability
check any longer.  This CL updates existing tabIndex() callsites to
avoid behavior changes.

Change-Id: Ib1728d6be98ccf589fc0e3e153d07eb973532e25
Bug: 982350
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1883350
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710206}