Removes most aura dependencies from WindowResizer

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 af7a92c558fcbeddcac9dc083f13bfbb3e50b205..39a47a8b40a3f0a2ed5740bcab7490a2c33f06ca 100644
--- a/ash/wm/window_resizer.h
+++ b/ash/wm/window_resizer.h
@@ -11,14 +11,20 @@
 #include "ash/wm/drag_details.h"
 #include "ash/wm/window_state.h"
 #include "base/macros.h"
-#include "ui/gfx/geometry/rect.h"
 #include "ui/wm/public/window_move_client.h"
 
 namespace aura {
 class Window;
 }
 
+namespace gfx {
+class Rect;
+}
+
 namespace ash {
+namespace wm {
+class WmWindow;
+}
 
 // WindowResizer is used by ToplevelWindowEventFilter to handle dragging, moving
 // or resizing a window. All coordinates passed to this are in the parent
@@ -35,7 +41,7 @@ class ASH_EXPORT WindowResizer {
   static const int kBoundsChangeDirection_Horizontal;
   static const int kBoundsChangeDirection_Vertical;
 
-  WindowResizer(wm::WindowState* window_state);
+  explicit WindowResizer(wm::WindowState* window_state);
   virtual ~WindowResizer();
 
   // Returns a bitmask of the kBoundsChange_ values.
@@ -56,8 +62,13 @@ class ASH_EXPORT WindowResizer {
   virtual void RevertDrag() = 0;
 
   // Returns the target window the resizer was created for.
-  aura::Window* GetTarget() const {
-    return window_state_ ? window_state_->aura_window() : NULL;
+  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|.