mash: Migrate AccessibilityDelegate access to WmShell.

ash/accelerators/spoken_feedback_toggler.cc

Index: ash/accelerators/spoken_feedback_toggler.cc
diff --git a/ash/accelerators/spoken_feedback_toggler.cc b/ash/accelerators/spoken_feedback_toggler.cc
index 942208a4117d5fa112195ab5bc095ef5528e79e5..7b7d0d5279f57c697fd55ab92b82a487ef81ed59 100644
--- a/ash/accelerators/spoken_feedback_toggler.cc
+++ b/ash/accelerators/spoken_feedback_toggler.cc
@@ -9,7 +9,7 @@
 #include "ash/accelerators/key_hold_detector.h"
 #include "ash/common/accessibility_delegate.h"
 #include "ash/common/accessibility_types.h"
-#include "ash/shell.h"
+#include "ash/common/wm_shell.h"
 #include "ui/events/event.h"
 
 namespace ash {
@@ -53,7 +53,7 @@ bool SpokenFeedbackToggler::ShouldStopEventPropagation() const {
 void SpokenFeedbackToggler::OnKeyHold(const ui::KeyEvent* event) {
   if (!toggled_) {
     toggled_ = true;
-    Shell::GetInstance()->accessibility_delegate()->ToggleSpokenFeedback(
+    WmShell::Get()->GetAccessibilityDelegate()->ToggleSpokenFeedback(
         A11Y_NOTIFICATION_SHOW);
   }
 }