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 76525064a7e34ab110e46752ecb27228656ec21a..dd41ee011bfd0f2cfe1da2299ffc8a3e4e65506e 100644
--- a/ui/views/controls/button/custom_button.cc
+++ b/ui/views/controls/button/custom_button.cc
@@ -331,6 +331,17 @@ void CustomButton::AnimationProgressed(const gfx::Animation* animation) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// CustomButton, views::InkDropHost implementation:
+
+void CustomButton::AddInkDropLayer(ui::Layer* ink_drop_layer) {}
+
+void CustomButton::RemoveInkDropLayer(ui::Layer* ink_drop_layer) {}

[Peter Kasting, 2015/12/28 13:44:33]

Having to override these just to give empty implementations somewhat suggests to
me that the InkDropHost base class should just define these as the default
implementations (instead of declaring these two functions pure virtual).

[bruthig, 2015/12/28 17:36:16]

I agree that would simplify things but I thought the style guidelines didn't
allow multiple inheritance?

[Peter Kasting, 2015/12/28 17:38:41]

I don't consider this to be qualitatively different than what you're doing (it's
not as if you're pulling in multiple complicated base implementations that you
should have used composition for instead), and Chromium does this sort of thing
in a zillion places already.  I say go for it.

[bruthig, 2015/12/28 18:35:40]

Done.

+
+gfx::Point CustomButton::CalculateInkDropCenter() const {
+  return GetLocalBounds().CenterPoint();
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // CustomButton, protected:
 
 CustomButton::CustomButton(ButtonListener* listener)