More precise use of multiline state

chrome/browser/resources/chromeos/chromevox/cvox2/background/editing_test.extjs

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/editing_test.extjs
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/editing_test.extjs b/chrome/browser/resources/chromeos/chromevox/cvox2/background/editing_test.extjs
index 6bfb586ce35c6eb8a0fd9e5eaad91991af31c3b6..ca1524e558c51628e1a660208b714f2f7e611546 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/editing_test.extjs
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/editing_test.extjs
@@ -163,7 +163,8 @@ TEST_F('EditingTest', 'TextButNoSelectionChange', function() {
 
 TEST_F('EditingTest', 'OneLineBreak', function() {
   this.assertLineData(function() {/*!
-      <div role="textbox" contenteditable>this is a<br>test</div>
+      <div role="textbox" contenteditable aria-multiline="true">
+          this is a<br>test</div>
     */},
     [
       {start: 0, end: 9, text: 'this is a'},
@@ -173,8 +174,8 @@ TEST_F('EditingTest', 'OneLineBreak', function() {
 
 TEST_F('EditingTest', 'TwoLineBreaks', function() {
   this.assertLineData(function() {/*!
-      <div role="textbox" contenteditable>this is a<br><br>
-          test</div>
+      <div role="textbox" contenteditable aria-multiline="true">
+          this is a<br><br>test</div>
     */},
     [
       {start: 0, end: 9, text: 'this is a'},
@@ -185,7 +186,7 @@ TEST_F('EditingTest', 'TwoLineBreaks', function() {
 
 TEST_F('EditingTest', 'InitialBreaks', function() {
   this.assertLineData(function() {/*!
-      <div role="textbox" contenteditable><br><br><br>
+      <div role="textbox" contenteditable aria-multiline="true"><br><br><br>
         this is a</div>
     */},
     [
@@ -198,7 +199,7 @@ TEST_F('EditingTest', 'InitialBreaks', function() {
 
 TEST_F('EditingTest', 'SingleCharacterLine', function() {
   this.assertLineData(function() {/*!
-      <div role="textbox" contenteditable>
+      <div role="textbox" contenteditable aria-multiline="true">

[David Tseng, 2017/07/01 01:17:40]

This is a pretty bad example to do this. The contenteditable clearly has
multiple lines and no event listeners to intercept key events.

The practical result of this is that ChromeVox can no longer rely upon the
multiline attribute for anything in contenteditables.

I think what would be a better justification of this change is to try collecting
some stats of real world usage. How many pages have contenteditables with role
textbox and how many of them are single lined?

Also, even if a page author intercepts all key events, if I type enough text
into the content editable, it will wrap (making it a multi line value). A author
would have to go pretty far to make the content editable "single" lined.
I could also paste multiple lines into the contet editable.

So, basically an author would have to:
- intercept at least enter (key event)
- make the content editable not wrap
- intercept paste
- hope no one inserts text with a content script

         <div>this</div><br>
         <div><br>
             I<br>