Makes WorkspaceWindowResizer use ash/wm/common types

ash/wm/aura/wm_window_aura.h

Index: ash/wm/aura/wm_window_aura.h
diff --git a/ash/wm/aura/wm_window_aura.h b/ash/wm/aura/wm_window_aura.h
index 5d033cadb64f55db51d6cedc670e6c90bfb100fa..9638cc4dffe19c1d0ec52282be1da0fe010449ec 100644
--- a/ash/wm/aura/wm_window_aura.h
+++ b/ash/wm/aura/wm_window_aura.h
@@ -25,6 +25,9 @@ class ASH_EXPORT WmWindowAura : public WmWindow, public aura::WindowObserver {
   // be null, in which case null is returned.
   static WmWindow* Get(aura::Window* window);
 
+  static std::vector<WmWindow*> FromAuraWindows(
+      const std::vector<aura::Window*>& aura_windows);
+
   static aura::Window* GetAuraWindow(WmWindow* wm_window) {
     return const_cast<aura::Window*>(
         GetAuraWindow(const_cast<const WmWindow*>(wm_window)));