Don't ignore <legend>

Bug: None
Change-Id: I680ebf6ce2561632a2bd937e03298b4e4f30e573
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2512602
Commit-Queue: Nektarios Paisios <nektar@chromium.org>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845583}

content/test/data/accessibility/html/fieldset-expected-android.txt

 android.webkit.WebView focusable focused scrollable
 ++android.view.View
 ++++android.view.View name='Browser Engines:'
-++++++android.view.View name='Browser Engines:'
+++++++android.view.View name='Browser Engines:'
\ No newline at end of file
+++android.view.View name='Which cake do you prefer?'
+++++android.view.View
+++++++android.view.View role_description='heading 2' heading name='Which cake do you prefer?'
\ No newline at end of file

content/test/data/accessibility/html/fieldset-expected-auralinux.txt

@@ -3,3 +3,7 @@
 ++++[panel] name='Browser Engines:' labelled-by
 ++++++[label] label-for
 ++++++++[static] name='Browser Engines:'
+++[panel] name='Which cake do you prefer?' labelled-by
+++++[label] label-for
+++++++[heading] name='Which cake do you prefer?'
+++++++++[static] name='Which cake do you prefer?'
\ No newline at end of file

content/test/data/accessibility/html/fieldset-expected-blink.txt

@@ -6,3 +6,8 @@ rootWebArea
 ++++++++++legend
 ++++++++++++staticText name='Browser Engines:'
 ++++++++++++++inlineTextBox name='Browser Engines:'
+++++++group name='Which cake do you prefer?'
+++++++++legend
+++++++++++heading name='Which cake do you prefer?'
+++++++++++++staticText name='Which cake do you prefer?'
+++++++++++++++inlineTextBox name='Which cake do you prefer?'
\ No newline at end of file

content/test/data/accessibility/html/fieldset-expected-mac.txt

@@ -3,3 +3,7 @@ AXWebArea
 ++++AXGroup AXDescription='Browser Engines:'
 ++++++AXGroup
 ++++++++AXStaticText AXValue='Browser Engines:'
+++AXGroup AXDescription='Which cake do you prefer?'
+++++AXGroup
+++++++AXHeading AXTitle='Which cake do you prefer?' AXValue=2
+++++++++AXStaticText AXValue='Which cake do you prefer?'
\ No newline at end of file

content/test/data/accessibility/html/fieldset-expected-uia-win.txt

@@ -3,3 +3,7 @@ Document
 ++++Group Name='Browser Engines:'
 ++++++Text IsControlElement=false
 ++++++++Text Name='Browser Engines:' IsControlElement=false
+++Group Name='Which cake do you prefer?'
+++++Text IsControlElement=false
+++++++Text Name='Which cake do you prefer?'
+++++++++Text Name='Which cake do you prefer?' IsControlElement=false
\ No newline at end of file

content/test/data/accessibility/html/fieldset-expected-win.txt

@@ -3,3 +3,7 @@ ROLE_SYSTEM_DOCUMENT READONLY FOCUSABLE
 ++++ROLE_SYSTEM_GROUPING name='Browser Engines:'
 ++++++IA2_ROLE_LABEL
 ++++++++ROLE_SYSTEM_STATICTEXT name='Browser Engines:'
+++ROLE_SYSTEM_GROUPING name='Which cake do you prefer?'
+++++IA2_ROLE_LABEL
+++++++IA2_ROLE_HEADING name='Which cake do you prefer?'
+++++++++ROLE_SYSTEM_STATICTEXT name='Which cake do you prefer?'
\ No newline at end of file

content/test/data/accessibility/html/fieldset.html

@@ -8,5 +8,11 @@
  </fieldset>
 </form>
 
+<fieldset>
+    <legend>
+        <h2>Which cake do you prefer?</h2>
+    </legend>
+</fieldset>
+
 </body>
 </html>

third_party/blink/renderer/modules/accessibility/ax_node_object.cc

@@ -379,6 +379,10 @@ AXObjectInclusion AXNodeObject::ShouldIncludeBasedOnSemantics(
   if (IsA<HTMLLabelElement>(node))
     return kIncludeObject;
 
+  // Don't ignored legends, because JAWS uses them to determine redundant text.
+  if (IsA<HTMLLegendElement>(node))
+    return kIncludeObject;
+
   // Anything that is content editable should not be ignored.
   // However, one cannot just call node->hasEditableStyle() since that will ask
   // if its parents are also editable. Only the top level content editable