Make ToggleImageButton into an accessible toggle button.

ui/views/controls/button/image_button.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 "ui/views/controls/button/image_button.h"
 
 #include <utility>
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_view_state.h"
@@ skipping 197 matching lines @@
     return;
 
   for (int i = 0; i < STATE_COUNT; ++i) {
     gfx::ImageSkia temp = images_[i];
     images_[i] = alternate_images_[i];
     alternate_images_[i] = temp;
   }
   toggled_ = toggled;
   SchedulePaint();
 
-  NotifyAccessibilityEvent(ui::AX_EVENT_VALUE_CHANGED, true);
+  NotifyAccessibilityEvent(ui::AX_EVENT_ARIA_ATTRIBUTE_CHANGED, true);
 }
 
 void ToggleImageButton::SetToggledImage(ButtonState image_state,
                                         const gfx::ImageSkia* image) {
   if (toggled_) {
     images_[image_state] = image ? *image : gfx::ImageSkia();
     if (state() == image_state)
       SchedulePaint();
   } else {
     alternate_images_[image_state] = image ? *image : gfx::ImageSkia();
@@ skipping 34 matching lines @@
   if (!toggled_ || toggled_tooltip_text_.empty())
     return Button::GetTooltipText(p, tooltip);
 
   *tooltip = toggled_tooltip_text_;
   return true;
 }
 
 void ToggleImageButton::GetAccessibleState(ui::AXViewState* state) {
   ImageButton::GetAccessibleState(state);
   GetTooltipText(gfx::Point(), &state->name);
+
+  // Some subclasses only ever have one state. To get ChromeVox to read
+  // appropriately, only change the role when this control is toggled on.
+  if (toggled_) {
+    state->role = ui::AX_ROLE_TOGGLE_BUTTON;
+    state->AddStateFlag(ui::AX_STATE_PRESSED);
+  }
 }
 
 }  // namespace views