Add ink drop masking to TrayBackgroundView

ui/views/animation/ink_drop_impl.h

Index: ui/views/animation/ink_drop_impl.h
diff --git a/ui/views/animation/ink_drop_impl.h b/ui/views/animation/ink_drop_impl.h
index 698e44c9634194bc85f1ffa2148751a63880665a..2f7fbda499e738589a90de24750a7cc582919716 100644
--- a/ui/views/animation/ink_drop_impl.h
+++ b/ui/views/animation/ink_drop_impl.h
@@ -45,11 +45,12 @@ class VIEWS_EXPORT InkDropImpl : public InkDrop,
   };
 
   // Constructs an ink drop that will attach the ink drop to the given
-  // |ink_drop_host|.
+  // |ink_drop_host|. |layer_size| determines size of the ink drop layer and
+  // should match the host size;
   //
   // By default the highlight will be made visible while |this| is hovered but
   // not focused and the NONE AutoHighlightMode will be used.
-  explicit InkDropImpl(InkDropHost* ink_drop_host);
+  InkDropImpl(InkDropHost* ink_drop_host, const gfx::Size& layer_size);

[bruthig, 2016/11/14 19:09:38]

nit: Rename |layer_size| as |host_size|.  Clients don't need to know what the
size is being used for.

[mohsen, 2016/11/14 20:19:39]

Done.

   ~InkDropImpl() override;
 
   void SetShowHighlightOnHover(bool show_highlight_on_hover);
@@ -66,6 +67,7 @@ class VIEWS_EXPORT InkDropImpl : public InkDrop,
   void SetAutoHighlightMode(AutoHighlightMode auto_highlight_mode);
 
   // InkDrop:
+  void UpdateLayerSize(const gfx::Size& layer_size) override;
   InkDropState GetTargetInkDropState() const override;
   void AnimateToState(InkDropState ink_drop_state) override;
   void SnapToActivated() override;