The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/86d6a59ab1f65dfb53f8292d385ba88b10eaa272

commit 86d6a59ab1f65dfb53f8292d385ba88b10eaa272
Author: Dominic Mazzoni <dmazzoni@chromium.org>
Date: Mon Apr 09 20:22:18 2018

Android accessibility: prefer "hint" for text fields labels.

Android's AccessibilityNodeInfo does not have a separate field
for the value of a text field, but it does have a "hint" field.

Suppose a text field has some accessible label - like a
aria-label or a placeholder. Previously Chrome exposed that
as the field's text if the field was empty, and the hint if
the field had user-entered text. This is confusing because
once the user starts entering text, the label jumps from the
text to the hint.

Instead, always expose the label as the hint, and let the
text be empty initially.

BUG= 828969 
TBR=aleventhal@chromium.org

Change-Id: I4052a811d645a42b3fecf8e2e1a4b089a7da75b8
Reviewed-on: https://chromium-review.googlesource.com/994132
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549257}
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/browser/accessibility/browser_accessibility_android.cc
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/aria/aria-combobox-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/aria/aria-readonly-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/aria/input-text-aria-placeholder-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/html/contenteditable-with-no-descendants-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/html/input-text-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/html/input-text-name-calc-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/html/input-text-read-only-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/html/input-text-value-expected-android.txt
[modify] https://crrev.com/86d6a59ab1f65dfb53f8292d385ba88b10eaa272/content/test/data/accessibility/html/input-types-expected-android.txt