a11y/Mac: Add screenreader support for SubtleNotificationView announcements.

chrome/browser/ui/views/subtle_notification_view.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/subtle_notification_view.h"
 
 #include <memory>
 
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "ui/accessibility/ax_view_state.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/font_list.h"
 #include "ui/views/bubble/bubble_border.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/link.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/widget/widget.h"
+#include "ui/views/widget/widget_observer.h"
 
 namespace {
 
 // Space between the site info label and the link.
 const int kMiddlePaddingPx = 30;
 
 const int kOuterPaddingHorizPx = 40;
 const int kOuterPaddingVertPx = 8;
 
 // Partially-transparent background color.
 const SkColor kBackgroundColor = SkColorSetARGB(0xcc, 0x28, 0x2c, 0x32);
 
 // Spacing around the key name.
 const int kKeyNameMarginHorizPx = 7;
 const int kKeyNameBorderPx = 1;
 const int kKeyNameCornerRadius = 2;
 const int kKeyNamePaddingPx = 5;
 
+// Delimiter indicating there should be a segment displayed as a keyboard key.
+const char kKeyNameDelimiter[] = "|";
+
 }  // namespace
 
 // Class containing the instruction text. Contains fancy styling on the keyboard
 // key (not just a simple label).
 class SubtleNotificationView::InstructionView : public views::View {
  public:
   // Creates an InstructionView with specific text. |text| may contain one or
   // more segments delimited by a pair of pipes ('|'); each of these segments
   // will be displayed as a keyboard key. e.g., "Press |Alt|+|Q| to exit" will
   // have "Alt" and "Q" rendered as keys.
   InstructionView(const base::string16& text,
                   const gfx::FontList& font_list,
                   SkColor foreground_color,
                   SkColor background_color);
 
+  base::string16 text() const { return text_; }
   void SetText(const base::string16& text);
 
  private:
   // Adds a label to the end of the notification text. If |format_as_key|,
   // surrounds the label in a rounded-rect border to indicate that it is a
   // keyboard key.
   void AddTextSegment(const base::string16& text, bool format_as_key);
 
   const gfx::FontList& font_list_;
   SkColor foreground_color_;
@@ skipping 23 matching lines @@
 void SubtleNotificationView::InstructionView::SetText(
     const base::string16& text) {
   // Avoid replacing the contents with the same text.
   if (text == text_)
     return;
 
   RemoveAllChildViews(true);
 
   // Parse |text|, looking for pipe-delimited segment.
   std::vector<base::string16> segments =
-      base::SplitString(text, base::ASCIIToUTF16("|"), base::TRIM_WHITESPACE,
-                        base::SPLIT_WANT_ALL);
+      base::SplitString(text, base::ASCIIToUTF16(kKeyNameDelimiter),
+                        base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
   // SplitString() returns empty strings for zero-length segments, so given an
   // even number of pipes, there should always be an odd number of segments.
   // The exception is if |text| is entirely empty, in which case the returned
   // list is also empty (rather than containing a single empty string).
   DCHECK(segments.empty() || segments.size() % 2 == 1);
 
   // Add text segment, alternating between non-key (no border) and key (border)
   // formatting.
   bool format_as_key = false;
   for (const auto& segment : segments) {
@@ skipping 69 matching lines @@
 SubtleNotificationView::~SubtleNotificationView() {}
 
 void SubtleNotificationView::UpdateContent(
     const base::string16& instruction_text,
     const base::string16& link_text) {
   instruction_view_->SetText(instruction_text);
   instruction_view_->SetVisible(!instruction_text.empty());
   link_->SetText(link_text);
   link_->SetVisible(!link_text.empty());
   Layout();
+
+  NotifyAccessibilityEvent(ui::AX_EVENT_CHILDREN_CHANGED, true);
+  NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
 }
 
 // static
 views::Widget* SubtleNotificationView::CreatePopupWidget(
     gfx::NativeView parent_view,
     SubtleNotificationView* view,
     bool accept_events) {
   // Initialize the popup.
   views::Widget* popup = new views::Widget;
   views::Widget::InitParams params(views::Widget::InitParams::TYPE_POPUP);
   params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
   params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   params.parent = parent_view;
   params.accept_events = accept_events;
   popup->Init(params);
   popup->SetContentsView(view);
   // We set layout manager to nullptr to prevent the widget from sizing its
   // contents to the same size as itself. This prevents the widget contents from
   // shrinking while we animate the height of the popup to give the impression
   // that it is sliding off the top of the screen.
   // TODO(mgiuca): This probably isn't necessary now that there is no slide
   // animation. Remove it.
   popup->GetRootView()->SetLayoutManager(nullptr);
 
+  // Allow accessibility events to be sent when the view is shown.
+  popup->AddObserver(view);
+
   return popup;
 }
+
+void SubtleNotificationView::SetAccessibleName(
+    const base::string16& accessible_name) {
+  base::RemoveChars(accessible_name, base::ASCIIToUTF16(kKeyNameDelimiter),
+                    &accessible_name_);
+}
+
+void SubtleNotificationView::GetAccessibleState(ui::AXViewState* state) {
+  state->role = ui::AX_ROLE_LABEL_TEXT;
+
+  // If there is no accessible name set, use the displayed text, but ensure the
+  // '|' delimiters are removed.
+  if (accessible_name_.empty()) {
+    base::string16 accessible_name;
+    base::RemoveChars(instruction_view_->text(),
+                      base::ASCIIToUTF16(kKeyNameDelimiter), &accessible_name);
+    state->name = accessible_name;
+  } else {
+    state->name = accessible_name_;
+  }
+}
+
+void SubtleNotificationView::OnWidgetClosing(views::Widget* widget) {
+  if (widget && widget == GetWidget())
+    widget->RemoveObserver(this);
+}
+
+void SubtleNotificationView::OnWidgetVisibilityChanged(views::Widget* widget,
+                                                       bool visible) {
+  if (visible)
+    NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
+}