Make ToggleImageButton into an accessible toggle button.

ui/views/controls/button/image_button.cc

Index: ui/views/controls/button/image_button.cc
diff --git a/ui/views/controls/button/image_button.cc b/ui/views/controls/button/image_button.cc
index a9fda37f5b49ed642fbf086df347f75870b83ff8..bc5c6a38f7ec089a5ce0cc9fec7cddfcb71395ff 100644
--- a/ui/views/controls/button/image_button.cc
+++ b/ui/views/controls/button/image_button.cc
@@ -215,7 +215,7 @@ void ToggleImageButton::SetToggled(bool toggled) {
   toggled_ = toggled;
   SchedulePaint();
 
-  NotifyAccessibilityEvent(ui::AX_EVENT_VALUE_CHANGED, true);
+  NotifyAccessibilityEvent(ui::AX_EVENT_ARIA_ATTRIBUTE_CHANGED, true);
 }
 
 void ToggleImageButton::SetToggledImage(ButtonState image_state,
@@ -270,6 +270,13 @@ bool ToggleImageButton::GetTooltipText(const gfx::Point& p,
 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