Test accessibility alert event on infobars.

Bug: 1082217
Change-Id: I97159b1cb3b6ccf8c57f17f54d011447fa6db681
AX-Relnotes: n/a.
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2432027Reviewed-by: Trent Apted <tapted@chromium.org>
Commit-Queue: Jacobo Aragunde Pérez <jaragunde@igalia.com>
Cr-Commit-Position: refs/heads/master@{#811133}

chrome/browser/ui/views/infobars/infobar_view_unittest.cc

@@ -7,6 +7,7 @@
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/ui/views/infobars/infobar_container_view.h"
 #include "chrome/test/base/browser_with_test_window_test.h"
+#include "ui/views/test/ax_event_counter.h"
 
 class TestInfoBarDelegate : public infobars::InfoBarDelegate {
  public:
@@ -76,3 +77,10 @@ TEST_F(InfoBarViewTest, LayoutOnHiddenInfoBar) {
   DetachContainer();
   infobar->Layout();
 }
+
+TEST_F(InfoBarViewTest, AlertAccessibleEvent) {
+  views::test::AXEventCounter counter(views::AXEventManager::Get());
+  EXPECT_EQ(0, counter.GetCount(ax::mojom::Event::kAlert));
+  TestInfoBarDelegate::Create(infobar_service());
+  EXPECT_EQ(1, counter.GetCount(ax::mojom::Event::kAlert));
+}