Example: In Wikipedia articles, just below the article title and the text that says "From Wikipedia, the free encyclopedia", there are 3 hidden links for screen readers that are being read aloud in Select To Speak.

Plan as discussed with Dominic:
ax_tree.cc will set 'offscreen' to 'true' if an element has no size and is inheriting size from the ancestor. This will allow Select-to-Speak to ignore 'offscreen' nodes but won't change chromevox's behavior.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/40420a3891be73b60f765cb7e772e901de8d2ed0

commit 40420a3891be73b60f765cb7e772e901de8d2ed0
Author: Katie Dektar <katydek@google.com>
Date: Thu Oct 19 20:08:31 2017

Nodes of size 0 inherit size from ancestor and now are labeled offscreen.

This allows automation API users to determine if something should be
ignored because it isn't visible to the user. It generally applies to
elements with 0 height and overflow:hidden whose contents also have
no size.

Bug:  773851 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Ia656a5907191aaad71dd2315e3f60a21fbecb6d8
Reviewed-on: https://chromium-review.googlesource.com/726242
Commit-Queue: Katie Dektar <katydek@google.com>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510175}
[modify] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/chrome/browser/resources/chromeos/select_to_speak/select_to_speak.js
[modify] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
[modify] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/content/browser/accessibility/one_shot_accessibility_tree_search_unittest.cc
[add] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/content/test/data/accessibility/html/bounds-inherits-expected-blink.txt
[add] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/content/test/data/accessibility/html/bounds-inherits.html
[modify] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/ui/accessibility/ax_tree.cc
[modify] https://crrev.com/40420a3891be73b60f765cb7e772e901de8d2ed0/ui/accessibility/ax_tree_unittest.cc

ChromeOS Version 64.0.3262.2 (Official Build) canary (64-bit)
Firmware Version Google_Samus.6300.174.0

I verified that this is NOT fixed using these steps:

# Enable Select to Speak in Settings per these instructions: https://support.google.com/chromebook/answer/177893?hl=en#selecttospeak   
# Confirm location of hidden links: Launch ChromeVox, go to https://en.wikipedia.org/wiki/Cat, navigate until jump to links are found after "From Wikipedia, the free encyclopedia". Turn ChromeVox off and put focus off the hidden links. 
# Hold down search button while using the mouse to highlight the text before and after the location of the hidden links. I started at "From Wikipedia" and went until "For that album, see Cat 1 (album)."  
# Listen to verbalizations 
Expected: hidden links are not read
Actual: the following is read:
"From Wikipedia, the free encyclopedia, Jump to, navigation, search, This article..."

Setting to assigned back to the dev.  

Thanks Laura. Even though this fixed the "Basic HTML View" in Gmail, you are correct that the wikipedia links are still being discovered by Select-to-Speak.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/be172f0a8427ecd56bf20333f892cdd3cf4e9b1d

commit be172f0a8427ecd56bf20333f892cdd3cf4e9b1d
Author: Katie Dektar <katydek@google.com>
Date: Tue Nov 14 22:45:37 2017

Nodes are 'offscreen' when fully outside bounds of their parent.

Bug:  773851 
Change-Id: I91aedacc5d637c13ef9d2c29597684551d7ae6c4
Reviewed-on: https://chromium-review.googlesource.com/764533
Commit-Queue: Katie D <katie@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516474}
[modify] https://crrev.com/be172f0a8427ecd56bf20333f892cdd3cf4e9b1d/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
[add] https://crrev.com/be172f0a8427ecd56bf20333f892cdd3cf4e9b1d/content/test/data/accessibility/html/bounds-clips-expected-blink.txt
[add] https://crrev.com/be172f0a8427ecd56bf20333f892cdd3cf4e9b1d/content/test/data/accessibility/html/bounds-clips.html
[modify] https://crrev.com/be172f0a8427ecd56bf20333f892cdd3cf4e9b1d/ui/accessibility/ax_tree.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a8671260ecea052b2abf090750d07035808d9665

commit a8671260ecea052b2abf090750d07035808d9665
Author: Katie Dektar <katydek@google.com>
Date: Fri Nov 17 21:18:42 2017

Elements with no size are offscreen only if outside the screen.

Children of elements with no size are offscreen still by virtue
of being clipped.

This fixes <br> tags (lineBreak) being labeled 'offscreen',
as well as any size (0, 0) element that is on the screen.

Bug:  773851 
Change-Id: I3e2ed49d3b66b3eb3280f44fcf86315273cce485
Reviewed-on: https://chromium-review.googlesource.com/772900
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Katie D <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517558}
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/test/data/accessibility/html/bounds-clips-expected-blink.txt
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/test/data/accessibility/html/bounds-inherits-expected-blink.txt
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/test/data/accessibility/html/br-expected-android.txt
[add] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/test/data/accessibility/html/br-expected-blink.txt
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/test/data/accessibility/html/br-expected-win.txt
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/content/test/data/accessibility/html/br.html
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/ui/accessibility/ax_tree.cc
[modify] https://crrev.com/a8671260ecea052b2abf090750d07035808d9665/ui/accessibility/ax_tree_unittest.cc

Note: a8671260ecea052b2abf090750d07035808d9665 was reverted in 6b28e6efc7326aecefe34788525d97427903ef08 because of  Issue 786621  .

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d78e27c3ac49bb9b3c2d768d6b684a5729bac270

commit d78e27c3ac49bb9b3c2d768d6b684a5729bac270
Author: Katie Dektar <katydek@google.com>
Date: Mon Nov 27 19:16:35 2017

Undo "Revert "Elements with no size are offscreen only if outside the screen.""

This reverts commit 6b28e6efc7326aecefe34788525d97427903ef08.

Original change:
https://chromium-review.googlesource.com/c/chromium/src/+/772900
Revert: https://chromium-review.googlesource.com/c/chromium/src/+/778131

Failing / flaky test fixed.

TBR=dmazzoni@chromium.org,jburdorick@chromium.org,aleventhal@chromium.org

Bug:  773851 
Change-Id: I9ae7f96f7f02c0f1e143c20eb5cb6ea4b0ca19df
Reviewed-on: https://chromium-review.googlesource.com/790755
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Katie D <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519359}
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/event/live-region-remove-expected-win.txt
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/html/bounds-clips-expected-blink.txt
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/html/bounds-inherits-expected-blink.txt
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/html/br-expected-android.txt
[add] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/html/br-expected-blink.txt
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/html/br-expected-win.txt
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/content/test/data/accessibility/html/br.html
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/ui/accessibility/ax_tree.cc
[modify] https://crrev.com/d78e27c3ac49bb9b3c2d768d6b684a5729bac270/ui/accessibility/ax_tree_unittest.cc