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

ash/shelf/shelf.cc

Index: ash/shelf/shelf.cc
diff --git a/ash/shelf/shelf.cc b/ash/shelf/shelf.cc
index e6ca53ea4bfb7c074c2c712f262f1affa36cfff6..05dcbcf455665978bbc1a0a01d01c379eb4b3bf9 100644
--- a/ash/shelf/shelf.cc
+++ b/ash/shelf/shelf.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 #include <cmath>
 
+#include "ash/aura/wm_window_aura.h"
 #include "ash/common/shelf/shelf_item_delegate.h"
 #include "ash/common/shelf/shelf_item_delegate_manager.h"
 #include "ash/common/shelf/shelf_model.h"
@@ -95,7 +96,7 @@ void Shelf::SetAlignment(ShelfAlignment alignment) {
   shelf_widget_->OnShelfAlignmentChanged();
   delegate_->OnShelfAlignmentChanged(this);
   Shell::GetInstance()->OnShelfAlignmentChanged(
-      shelf_widget_->GetNativeWindow()->GetRootWindow());
+      WmWindowAura::Get(shelf_widget_->GetNativeWindow()->GetRootWindow()));
   // ShelfLayoutManager will resize the shelf.
 }
 
@@ -110,7 +111,7 @@ void Shelf::SetAutoHideBehavior(ShelfAutoHideBehavior auto_hide_behavior) {
   auto_hide_behavior_ = auto_hide_behavior;
   delegate_->OnShelfAutoHideBehaviorChanged(this);
   Shell::GetInstance()->OnShelfAutoHideBehaviorChanged(
-      shelf_widget_->GetNativeWindow()->GetRootWindow());
+      WmWindowAura::Get(shelf_widget_->GetNativeWindow()->GetRootWindow()));
 }
 
 ShelfAutoHideState Shelf::GetAutoHideState() const {