Refactors DimWindow and moves to ash/common

ash/aura/wm_window_aura.cc

Index: ash/aura/wm_window_aura.cc
diff --git a/ash/aura/wm_window_aura.cc b/ash/aura/wm_window_aura.cc
index f923414d7fe790cb5b17b0c18d99b55e00e06b5e..e4c6b75a7a16d072a3542d81c1f9c50559a9a3db 100644
--- a/ash/aura/wm_window_aura.cc
+++ b/ash/aura/wm_window_aura.cc
@@ -135,6 +135,11 @@ const aura::Window* WmWindowAura::GetAuraWindow(const WmWindow* wm_window) {
                    : nullptr;
 }
 
+void WmWindowAura::Destroy() {
+  delete window_;
+  // WARNING: this has been deleted.
+}
+
 const WmWindow* WmWindowAura::GetRootWindow() const {
   return Get(window_->GetRootWindow());
 }
@@ -365,6 +370,10 @@ WmLayoutManager* WmWindowAura::GetLayoutManager() {
   return adapter ? adapter->wm_layout_manager() : nullptr;
 }
 
+void WmWindowAura::SetVisibilityChangesAnimated() {
+  ::wm::SetWindowVisibilityChangesAnimated(window_);
+}
+
 void WmWindowAura::SetVisibilityAnimationType(int type) {
   ::wm::SetWindowVisibilityAnimationType(window_, type);
 }