Converts ShellObserver from aura::Window to ash::WmWindow

chrome/browser/chromeos/accessibility/accessibility_manager.cc

Index: chrome/browser/chromeos/accessibility/accessibility_manager.cc
diff --git a/chrome/browser/chromeos/accessibility/accessibility_manager.cc b/chrome/browser/chromeos/accessibility/accessibility_manager.cc
index fc1eea799e41ca6bb225ab0b32c760a3a77f708c..687ee4a3322908c0f64894eac7a5e4c942681e11 100644
--- a/chrome/browser/chromeos/accessibility/accessibility_manager.cc
+++ b/chrome/browser/chromeos/accessibility/accessibility_manager.cc
@@ -1280,8 +1280,9 @@ void AccessibilityManager::OnAppTerminating() {
   session_state_observer_.reset();
 }
 
-void AccessibilityManager::OnFullscreenStateChanged(bool is_fullscreen,
-                                                    aura::Window* root_window) {
+void AccessibilityManager::OnFullscreenStateChanged(
+    bool is_fullscreen,
+    ash::WmWindow* root_window) {
   if (chromevox_panel_)
     chromevox_panel_->UpdateWidgetBounds();
 }