Add test for accessibility window activated event.

This is a tricky test due to the asynchronous nature of the event. It
is produced in response to a system window event, so we need the test
to produce an actual window so we can listen to it, and we need to add
a way to wait for it.

Bug: None
Change-Id: If7cd10c5db282f7cc465505286790ab1f4b458a2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2370984
Commit-Queue: Jacobo Aragunde Pérez <jaragunde@igalia.com>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804550}

chrome/browser/ui/views/frame/browser_view_interactive_uitest.cc

@@ -13,8 +13,11 @@
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/test/browser_test.h"
+#include "ui/views/buildflags.h"
+#include "ui/views/test/ax_event_counter.h"
 
 #if defined(OS_MAC)
 #include "chrome/browser/ui/browser_commands_mac.h"
@@ -27,8 +30,10 @@ namespace {
 
 class BrowserViewTest : public InProcessBrowserTest {
  public:
-  BrowserViewTest() = default;
+  BrowserViewTest() : ax_observer_(views::AXEventManager::Get()) {}
   ~BrowserViewTest() override = default;
+  BrowserViewTest(const BrowserViewTest&) = delete;
+  BrowserViewTest& operator=(const BrowserViewTest&) = delete;
 
   void SetUpOnMainThread() override {
 #if defined(OS_MAC)
@@ -44,8 +49,8 @@ class BrowserViewTest : public InProcessBrowserTest {
 #endif
   }
 
- private:
-  DISALLOW_COPY_AND_ASSIGN(BrowserViewTest);
+ protected:
+  views::test::AXEventCounter ax_observer_;
 };
 
 }  // namespace
@@ -219,3 +224,26 @@ IN_PROC_BROWSER_TEST_F(BrowserViewTest, FullscreenShowBookmarkBar) {
   EXPECT_TRUE(browser_view->IsTabStripVisible());
   EXPECT_TRUE(browser_view->IsBookmarkBarVisible());
 }
+
+// TODO(crbug.com/897177): Only Aura platforms use the WindowActivated
+// accessibility event. We need to harmonize the firing of accessibility events
+// between platforms.
+#if BUILDFLAG(ENABLE_DESKTOP_AURA)
+IN_PROC_BROWSER_TEST_F(BrowserViewTest, WindowActivatedAccessibleEvent) {
+  // Wait for window activated event from the first browser window.
+  // This event is asynchronous, it is emitted as a response to a system window
+  // event. It is possible that we haven't received it yet when we run this test
+  // and we need to explicitly wait for it.
+  if (ax_observer_.GetCount(ax::mojom::Event::kWindowActivated) == 0)
+    ax_observer_.WaitForEvent(ax::mojom::Event::kWindowActivated);
+  ASSERT_EQ(1, ax_observer_.GetCount(ax::mojom::Event::kWindowActivated));
+
+  // Create a new browser window and wait for event again.
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(url::kAboutBlankURL), WindowOpenDisposition::NEW_WINDOW,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_BROWSER);
+  if (ax_observer_.GetCount(ax::mojom::Event::kWindowActivated) == 1)
+    ax_observer_.WaitForEvent(ax::mojom::Event::kWindowActivated);
+  ASSERT_EQ(2, ax_observer_.GetCount(ax::mojom::Event::kWindowActivated));
+}
+#endif

ui/views/test/ax_event_counter.cc

@@ -16,11 +16,23 @@ AXEventCounter::~AXEventCounter() = default;
 
 void AXEventCounter::OnViewEvent(views::View*, ax::mojom::Event event_type) {
   ++event_counts_[event_type];
+  if (run_loop_ && event_type == wait_for_event_type_) {
+    wait_for_event_type_ = ax::mojom::Event::kNone;
+    run_loop_->Quit();
+  }
 }
 
 int AXEventCounter::GetCount(ax::mojom::Event event_type) {
   return event_counts_[event_type];
 }
 
+void AXEventCounter::WaitForEvent(ax::mojom::Event event_type) {
+  wait_for_event_type_ = event_type;
+  base::RunLoop run_loop;
+  run_loop_ = &run_loop;
+  run_loop_->Run();
+  run_loop_ = nullptr;
+}
+
 }  // namespace test
 }  // namespace views

ui/views/test/ax_event_counter.h

@@ -6,7 +6,9 @@
 #define UI_VIEWS_TEST_AX_EVENT_COUNTER_H_
 
 #include "base/containers/flat_map.h"
+#include "base/run_loop.h"
 #include "base/scoped_observer.h"
+#include "ui/accessibility/ax_enums.mojom.h"
 #include "ui/views/accessibility/ax_event_manager.h"
 #include "ui/views/accessibility/ax_event_observer.h"
 
@@ -14,7 +16,7 @@ namespace views {
 namespace test {
 
 // AXEventCounter provides a convenient way to count events registered by the
-// AXEventManager by their event type.
+// AXEventManager by their event type, and wait for events of a specific type.
 class AXEventCounter : public views::AXEventObserver {
  public:
   explicit AXEventCounter(views::AXEventManager* event_manager);
@@ -27,11 +29,16 @@ class AXEventCounter : public views::AXEventObserver {
   // creation of this AXEventManager object.
   int GetCount(ax::mojom::Event event_type);
 
+  // Blocks until an event of the specified type is received.
+  void WaitForEvent(ax::mojom::Event event_type);
+
   // views::AXEventObserver
   void OnViewEvent(views::View*, ax::mojom::Event event_type) override;
 
  private:
   base::flat_map<ax::mojom::Event, int> event_counts_;
+  ax::mojom::Event wait_for_event_type_ = ax::mojom::Event::kNone;
+  base::RunLoop* run_loop_ = nullptr;
   ScopedObserver<views::AXEventManager, views::AXEventObserver> tree_observer_{
       this};
 };