MacViews: Put wm window animation calls behind an interface.

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

Index: ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index 2d57f738a42f8b9855ac82d1e0711194843a7878..2e0309f7f05b4675c22aba19c13dd34e6d9265ca 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -46,6 +46,7 @@
 #include "ui/views/widget/widget_aura_utils.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/widget/window_reorderer.h"
+#include "ui/views/widget/window_visibility_animation_aura.h"
 #include "ui/views/window/native_frame_view.h"
 #include "ui/wm/core/compound_event_filter.h"
 #include "ui/wm/core/cursor_manager.h"
@@ -260,6 +261,7 @@ DesktopNativeWidgetAura::DesktopNativeWidgetAura(
       restore_focus_on_activate_(false),
       cursor_(gfx::kNullCursor),
       widget_type_(Widget::InitParams::TYPE_WINDOW),
+      visibility_animation_(new WindowVisibilityAnimationAura(content_window_)),
       close_widget_factory_(this) {
   aura::client::SetFocusChangeObserver(content_window_, this);
   aura::client::SetActivationChangeObserver(content_window_, this);
@@ -914,6 +916,11 @@ void DesktopNativeWidgetAura::SetVisibilityChangedAnimationsEnabled(
     desktop_window_tree_host_->SetVisibilityChangedAnimationsEnabled(value);
 }
 
+Widget::VisibilityAnimation* DesktopNativeWidgetAura::GetVisibilityAnimation()
+    const {
+  return visibility_animation_.get();
+}
+
 ui::NativeTheme* DesktopNativeWidgetAura::GetNativeTheme() const {
   return DesktopWindowTreeHost::GetNativeTheme(content_window_);
 }