Add ripples to md checkboxes/radio buttons

ui/views/controls/button/checkbox.cc

Index: ui/views/controls/button/checkbox.cc
diff --git a/ui/views/controls/button/checkbox.cc b/ui/views/controls/button/checkbox.cc
index c1db4715f33b532cdc2a7204ff02568972166a93..06570d89fb49f15633a32a44ee4ab6a41bb30136 100644
--- a/ui/views/controls/button/checkbox.cc
+++ b/ui/views/controls/button/checkbox.cc
@@ -15,6 +15,9 @@
 #include "ui/gfx/paint_vector_icon.h"
 #include "ui/gfx/vector_icons_public.h"
 #include "ui/resources/grit/ui_resources.h"
+#include "ui/views/animation/button_ink_drop_delegate.h"
+#include "ui/views/animation/ink_drop_hover.h"
+#include "ui/views/animation/ink_drop_ripple.h"
 #include "ui/views/controls/button/label_button_border.h"
 #include "ui/views/painter.h"
 #include "ui/views/resources/grit/views_resources.h"
@@ -32,6 +35,11 @@ Checkbox::Checkbox(const base::string16& label)
 
   if (UseMd()) {
     set_request_focus_on_press(false);
+    set_ink_drop_delegate(
+        base::WrapUnique(new ButtonInkDropDelegate(this, this)));
+    set_has_ink_drop_action_on_click(true);
+    // The "small" size is 21dp, the large size is 1.33 * 21dp = 28dp.
+    set_ink_drop_size(gfx::Size(21, 21));
   } else {
     std::unique_ptr<LabelButtonBorder> button_border(new LabelButtonBorder());
     // Inset the trailing side by a couple pixels for the focus border.
@@ -152,6 +160,24 @@ void Checkbox::OnNativeThemeChanged(const ui::NativeTheme* theme) {
     UpdateImage();
 }
 
+std::unique_ptr<InkDropRipple> Checkbox::CreateInkDropRipple() const {
+  // Skip over the LabelButton override.
+  return InkDropHostView::CreateInkDropRipple();
+}
+
+std::unique_ptr<InkDropHover> Checkbox::CreateInkDropHover() const {
+  return nullptr;
+}
+
+gfx::Point Checkbox::GetInkDropCenter() const {
+  return image()->bounds().CenterPoint();
+}
+
+SkColor Checkbox::GetInkDropBaseColor() const {
+  return GetNativeTheme()->GetSystemColor(
+      ui::NativeTheme::kColorId_UnfocusedBorderColor);

[sky, 2016/06/02 03:13:30]

This seems like a weird choice for a base color. I'm assuming you know what
you're doing.

[Evan Stade, 2016/06/02 19:40:18]

How so? It's the color of the checkbox square/radio circle. In other places like
the bookmark bar folder buttons we use the color of the icon, so this seems like
the most natural choice.
I hope you're right.

[sky, 2016/06/02 21:47:59]

I didn't realize we use 'unfocused border color' in those places. IMO 'unfocused
border color' isn't a descriptive name for a color used as a base in many
places. But I realize naming is hard.

+}
+
 gfx::ImageSkia Checkbox::GetImage(ButtonState for_state) const {
   if (UseMd()) {
     return gfx::CreateVectorIcon(