Quoting: aria-valuemax now has a default implicit value on some roles (when author does not specify aria-valuemax):
scrollbar is 100
separator is 100
slider is 100
spinbutton is 100
Note that progress meter is not listed here.

Need clarification on spec: we need to understand whether this default value takes precedence over an HTML-provided max attribute. Reading the spec strictly would indicate yes, but it doesn't seem appropriate to override any author provided max.

Agreed that the spec is unclear, but I'm pretty sure that what's intended is that if there is no author-provided max, 100 should be the default.

This still seems to me like a good first bug. I wouldn't wait on the spec to start working on it.

Hi all,
I've updated patch for current issue as below.
https://chromium-review.googlesource.com/c/chromium/src/+/647353

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/15c97cd87a3029cdb80f148d9d420790178297e3

commit 15c97cd87a3029cdb80f148d9d420790178297e3
Author: DongJun Kim <djmix.kim@samsung.com>
Date: Mon Sep 18 17:49:35 2017

Change default value of aria-valuemax on some roles

According from ARIA 1.1 [1],
default value of scrollbar, separator and slider
for aria-valuemax were changed to 100.

We return 100 as default when calling
AXNodeObject::MaxValueForRange() if not otherwise specified.

[1] https://www.w3.org/WAI/ARIA/wiki/ARIA_1.1_Changes

BUG= 688581 

Change-Id: I687889d03034d7d38dc33c7af64ea184a4f4e5fb
Reviewed-on: https://chromium-review.googlesource.com/647353
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502607}
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/content/test/data/accessibility/aria/aria-orientation-expected-android.txt
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/content/test/data/accessibility/aria/aria-orientation-expected-blink.txt
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/content/test/data/accessibility/aria/aria-readonly-expected-android.txt
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/content/test/data/accessibility/aria/aria-scrollbar-expected-android.txt
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/content/test/data/accessibility/aria/aria-scrollbar-expected-blink.txt
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/third_party/WebKit/LayoutTests/accessibility/aom-float-properties.html
[modify] https://crrev.com/15c97cd87a3029cdb80f148d9d420790178297e3/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

According comments from Aaron Leventhal,
It will be investigated continuously on "https://github.com/w3c/aria/issues/644".

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3a4f36179baee9b37d8132b7700b0f1699b40841

commit 3a4f36179baee9b37d8132b7700b0f1699b40841
Author: deejay <djmix.kim@samsung.com>
Date: Fri Sep 29 18:29:46 2017

Change default value of aria-level to 2

According from ARIA 1.1 [1],
default value of aria-level was changed to 2.

We will return 2 as default in aria-level
if not otherwise specified.

[1] https://www.w3.org/WAI/ARIA/wiki/ARIA_1.1_Changes

Bug= 688581 

Change-Id: Ib03c23f96b74814fe9f52f196c6e0e417059112f
Reviewed-on: https://chromium-review.googlesource.com/670539
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505425}
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/content/test/data/accessibility/aria/aria-heading-expected-android.txt
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/content/test/data/accessibility/aria/aria-heading-expected-blink.txt
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/content/test/data/accessibility/aria/aria-heading-expected-mac.txt
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/content/test/data/accessibility/aria/aria-heading-expected-win.txt
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/third_party/WebKit/LayoutTests/accessibility/heading-level-expected.txt
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/third_party/WebKit/LayoutTests/accessibility/heading-level.html
[modify] https://crrev.com/3a4f36179baee9b37d8132b7700b0f1699b40841/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

 Issue 688580  has been merged into this issue.