Add ink drop masking to TrayBackgroundView

ash/common/system/tray/tray_background_view.h

Index: ash/common/system/tray/tray_background_view.h
diff --git a/ash/common/system/tray/tray_background_view.h b/ash/common/system/tray/tray_background_view.h
index d7879f072324b2e1d5414ced0b40defb32951e15..e3c9500e20b519db6727ac9291a1aeab7b0ac5f4 100644
--- a/ash/common/system/tray/tray_background_view.h
+++ b/ash/common/system/tray/tray_background_view.h
@@ -15,6 +15,10 @@
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/views/bubble/tray_bubble_view.h"
 
+namespace views {
+class RoundRectInkDropMask;
+}
+
 namespace ash {
 class ShelfLayoutManager;
 class TrayEventFilter;
@@ -78,6 +82,8 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   void OnPaint(gfx::Canvas* canvas) override;
 
   // ActionableView:
+  void AddInkDropLayer(ui::Layer* ink_drop_layer) override;
+  void RemoveInkDropLayer(ui::Layer* ink_drop_layer) override;
   std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override;
   std::unique_ptr<views::InkDropHighlight> CreateInkDropHighlight()
       const override;
@@ -176,6 +182,8 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   std::unique_ptr<TrayWidgetObserver> widget_observer_;
   std::unique_ptr<TrayEventFilter> tray_event_filter_;
 
+  std::unique_ptr<views::RoundRectInkDropMask> ink_drop_mask_;

[bruthig, 2016/11/11 20:16:43]

Capturing offline discussion:
Let's move the ownership of the mask up to InkDropHostView and add an
override-able InkDropHost::CreateInkDropMask() method. If any subclass needs to
reference the mask by the correct type we can add an override-able
InkDropHost::OnInkDropMaskDestroyed() and allow the subclass to keep a reference
to the mask it returns from the Create function.

[mohsen, 2016/11/13 23:31:29]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(TrayBackgroundView);
 };