Makes Panel related classes use ash/wm/common types

ash/wm/window_resizer.h

Index: ash/wm/window_resizer.h
diff --git a/ash/wm/window_resizer.h b/ash/wm/window_resizer.h
index 2ca6f2a232559f310cf7cddf7647baa328533984..45607958c473f0eb6c9fb1ea18d63e3d505cdecd 100644
--- a/ash/wm/window_resizer.h
+++ b/ash/wm/window_resizer.h
@@ -13,10 +13,6 @@
 #include "base/macros.h"
 #include "ui/wm/public/window_move_client.h"
 
-namespace aura {
-class Window;
-}
-
 namespace gfx {
 class Rect;
 }
@@ -65,12 +61,6 @@ class ASH_EXPORT WindowResizer {
   wm::WmWindow* GetTarget() const {
     return window_state_ ? window_state_->window() : nullptr;
   }
-  // Deprecated.
-  // TODO(sky): remove.
-  aura::Window* GetAuraTarget() const {
-    return window_state_ ? window_state_->aura_window() : nullptr;
-  }
-
   // See comment for |DragDetails::initial_location_in_parent|.
   const gfx::Point& GetInitialLocation() const {
     return window_state_->drag_details()->initial_location_in_parent;