a11y/Mac: Add screenreader support for SubtleNotificationView announcements.

chrome/browser/ui/views/subtle_notification_view.h

Index: chrome/browser/ui/views/subtle_notification_view.h
diff --git a/chrome/browser/ui/views/subtle_notification_view.h b/chrome/browser/ui/views/subtle_notification_view.h
index c04296a91029066f04322064425481390ebb8cc4..535dd9d0e737d4955fbad8159b33ca807574d4c1 100644
--- a/chrome/browser/ui/views/subtle_notification_view.h
+++ b/chrome/browser/ui/views/subtle_notification_view.h
@@ -9,6 +9,11 @@
 #include "base/strings/string16.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/view.h"
+#include "ui/views/widget/widget_observer.h"
+
+namespace ui {
+struct AXViewState;
+}
 
 namespace views {
 class Link;
@@ -22,7 +27,8 @@ class Widget;
 // auto-dismisses after a short period of time. It also has special
 // functionality for displaying keyboard shortcuts (rendering the keys inside a
 // rounded rectangle).
-class SubtleNotificationView : public views::View {
+class SubtleNotificationView : public views::View,
+                               public views::WidgetObserver {
  public:
   explicit SubtleNotificationView(views::LinkListener* link_listener);
   ~SubtleNotificationView() override;
@@ -37,6 +43,17 @@ class SubtleNotificationView : public views::View {
                                           SubtleNotificationView* view,
                                           bool accept_events);
 
+  // Sets the accessible text for screenreaders to announce on displaying this
+  // notification, with unicode characters expanded.
+  void SetAccessibleName(const base::string16& accessible_name);
+
+  // views::View:
+  void GetAccessibleState(ui::AXViewState* state) override;
+
+  // views::WidgetObserver:
+  void OnWidgetClosing(views::Widget* widget) override;
+  void OnWidgetVisibilityChanged(views::Widget* widget, bool visible) override;
+
  private:
   class InstructionView;