Pushed InkDropHost inheritence up to CustomButton.

ui/views/controls/button/custom_button.cc

Index: ui/views/controls/button/custom_button.cc
diff --git a/ui/views/controls/button/custom_button.cc b/ui/views/controls/button/custom_button.cc
index 62fec14cbce91d26834649fe869231a99e9dbf97..db3fb5d7937355a3e247158834c9800bb7b3183f 100644
--- a/ui/views/controls/button/custom_button.cc
+++ b/ui/views/controls/button/custom_button.cc
@@ -331,6 +331,26 @@ void CustomButton::AnimationProgressed(const gfx::Animation* animation) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// CustomButton, views::InkDropHost implementation:
+
+void CustomButton::AddInkDropLayer(ui::Layer* ink_drop_layer) {
+  SetPaintToLayer(true);
+  SetFillsBoundsOpaquely(false);

[sadrul, 2016/01/06 19:18:45]

It shouldn't happen here. At most, this should DCHECK() that layer() exists.
Even then, I don't think it's entirely right.

Is there a reason a ButtonInkDropHost wouldn't work?

+  layer()->Add(ink_drop_layer);
+  layer()->StackAtBottom(ink_drop_layer);
+}
+
+void CustomButton::RemoveInkDropLayer(ui::Layer* ink_drop_layer) {
+  layer()->Remove(ink_drop_layer);
+  SetFillsBoundsOpaquely(true);
+  SetPaintToLayer(false);
+}
+
+gfx::Point CustomButton::CalculateInkDropCenter() const {
+  return GetLocalBounds().CenterPoint();
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // CustomButton, protected:
 
 CustomButton::CustomButton(ButtonListener* listener)