Implement accessible states and notifications for the tab strip.

chrome/browser/ui/views/tabs/tab_strip.cc

 // Copyright (c) 2012 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/tabs/tab_strip.h"
 
 #if defined(OS_WIN)
 #include <windowsx.h>
 #endif
 
@@ skipping 799 matching lines @@
     // We have "tiny tabs" if the tabs are so tiny that the unselected ones are
     // a different size to the selected ones.
     bool tiny_tabs = current_unselected_width_ != current_selected_width_;
     if (!IsAnimating() && (!in_tab_close_ || tiny_tabs)) {
       DoLayout();
     } else {
       SchedulePaint();
     }
   }
 
+  // Use STLSetDifference to get the indices of elements newly selected
+  // and no longer selected, since selected_indices() is always sorted.
   ui::ListSelectionModel::SelectedIndices no_longer_selected =
       base::STLSetDifference<ui::ListSelectionModel::SelectedIndices>(
           old_selection.selected_indices(),
           new_selection.selected_indices());
-  for (size_t i = 0; i < no_longer_selected.size(); ++i)
+  ui::ListSelectionModel::SelectedIndices newly_selected =
+      base::STLSetDifference<ui::ListSelectionModel::SelectedIndices>(
+          new_selection.selected_indices(),
+          old_selection.selected_indices());
+
+  // Fire accessibility events that reflect the changes to selection, and
+  // stop the mini tab title animation on tabs no longer selected.
+  for (size_t i = 0; i < no_longer_selected.size(); ++i) {
     tab_at(no_longer_selected[i])->StopMiniTabTitleAnimation();
+    tab_at(no_longer_selected[i])->NotifyAccessibilityEvent(
+        ui::AX_EVENT_SELECTION_REMOVE, true);
+  }
+  for (size_t i = 0; i < newly_selected.size(); ++i) {
+    tab_at(newly_selected[i])->NotifyAccessibilityEvent(
+        ui::AX_EVENT_SELECTION_ADD, true);
+  }
+  tab_at(new_selection.active())->NotifyAccessibilityEvent(
+      ui::AX_EVENT_SELECTION, true);
 }
 
 void TabStrip::TabTitleChangedNotLoading(int model_index) {
   Tab* tab = tab_at(model_index);
   if (tab->data().mini && !tab->IsActive())
     tab->StartMiniTabTitleAnimation();
 }
 
 int TabStrip::GetModelIndexOfTab(const Tab* tab) const {
   return tabs_.GetIndexOfView(tab);
@@ skipping 1851 matching lines @@
         action = TouchUMA::GESTURE_TABSWITCH_TAP;
       TouchUMA::RecordGestureAction(action);
       break;
     }
 
     default:
       break;
   }
   event->SetHandled();
 }