Added supporting code for Blink layout tests for isContentRichlyEditable.

components/test_runner/web_ax_object_proxy.cc

Index: components/test_runner/web_ax_object_proxy.cc
diff --git a/components/test_runner/web_ax_object_proxy.cc b/components/test_runner/web_ax_object_proxy.cc
index ae1281656f9643865470c69f72a0d5670ac6c2a1..125507be8688d29e7aac3825946036665414cde0 100644
--- a/components/test_runner/web_ax_object_proxy.cc
+++ b/components/test_runner/web_ax_object_proxy.cc
@@ -498,6 +498,7 @@ WebAXObjectProxy::GetObjectTemplateBuilder(v8::Isolate* isolate) {
                    &WebAXObjectProxy::SelectionEndLineNumber)
       .SetProperty("isEnabled", &WebAXObjectProxy::IsEnabled)
       .SetProperty("isRequired", &WebAXObjectProxy::IsRequired)
+      .SetProperty("isRichlyEditable", &WebAXObjectProxy::IsRichlyEditable)
       .SetProperty("isFocused", &WebAXObjectProxy::IsFocused)
       .SetProperty("isFocusable", &WebAXObjectProxy::IsFocusable)
       .SetProperty("isSelected", &WebAXObjectProxy::IsSelected)
@@ -760,6 +761,11 @@ bool WebAXObjectProxy::IsRequired() {
   return accessibility_object_.isRequired();
 }
 
+bool WebAXObjectProxy::IsRichlyEditable() {
+  accessibility_object_.updateLayoutAndCheckValidity();
+  return accessibility_object_.isRichlyEditable();
+}
+
 bool WebAXObjectProxy::IsFocused() {
   accessibility_object_.updateLayoutAndCheckValidity();
   return accessibility_object_.isFocused();