Refactor backdrop that is currently used in the maximized mode.

components/exo/wm_helper.cc

Index: components/exo/wm_helper.cc
diff --git a/components/exo/wm_helper.cc b/components/exo/wm_helper.cc
index 7f0cfcffe7264f5d77f685f28bacf65df824f359..46faffd93a4954c253c03c39523c9c9a1c59c1b6 100644
--- a/components/exo/wm_helper.cc
+++ b/components/exo/wm_helper.cc
@@ -62,14 +62,6 @@ void WMHelper::RemoveMaximizeModeObserver(MaximizeModeObserver* observer) {
   maximize_mode_observers_.RemoveObserver(observer);
 }
 
-void WMHelper::AddAccessibilityObserver(AccessibilityObserver* observer) {
-  accessibility_observers_.AddObserver(observer);
-}
-
-void WMHelper::RemoveAccessibilityObserver(AccessibilityObserver* observer) {
-  accessibility_observers_.RemoveObserver(observer);
-}
-
 void WMHelper::AddInputDeviceEventObserver(InputDeviceEventObserver* observer) {
   input_device_event_observers_.AddObserver(observer);
 }
@@ -126,11 +118,6 @@ void WMHelper::NotifyMaximizeModeEnded() {
     observer.OnMaximizeModeEnded();
 }
 
-void WMHelper::NotifyAccessibilityModeChanged() {
-  for (AccessibilityObserver& observer : accessibility_observers_)
-    observer.OnAccessibilityModeChanged();
-}
-
 void WMHelper::NotifyKeyboardDeviceConfigurationChanged() {
   for (InputDeviceEventObserver& observer : input_device_event_observers_)
     observer.OnKeyboardDeviceConfigurationChanged();