ui: Cleanup class/struct forward declarations

ash/common/system/tray/actionable_view.cc

Index: ash/common/system/tray/actionable_view.cc
diff --git a/ash/common/system/tray/actionable_view.cc b/ash/common/system/tray/actionable_view.cc
index f1d249416dd53afada5101785424ad2250407c29..07be3c018ee83d232b94863122483498c9e338f0 100644
--- a/ash/common/system/tray/actionable_view.cc
+++ b/ash/common/system/tray/actionable_view.cc
@@ -13,6 +13,7 @@
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/views/animation/flood_fill_ink_drop_ripple.h"
 #include "ui/views/animation/ink_drop_highlight.h"
+#include "ui/views/animation/ink_drop_impl.h"
 
 namespace ash {
 
@@ -80,6 +81,13 @@ void ActionableView::OnBlur() {
   SchedulePaint();
 }
 
+std::unique_ptr<views::InkDrop> ActionableView::CreateInkDrop() {
+  std::unique_ptr<views::InkDropImpl> ink_drop =
+      CreateDefaultFloodFillInkDropImpl();
+  ink_drop->SetShowHighlightOnHover(false);
+  return std::move(ink_drop);
+}
+
 std::unique_ptr<views::InkDropRipple> ActionableView::CreateInkDropRipple()
     const {
   return base::MakeUnique<views::FloodFillInkDropRipple>(