Added material design mouse hover feedback support.

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 3ab8303e9f8821d8dd77e1f7ba7308153cd78a60..e63619e6711613c27be17149b296994cde863f57 100644
--- a/ui/views/controls/button/custom_button.cc
+++ b/ui/views/controls/button/custom_button.cc
@@ -123,6 +123,8 @@ void CustomButton::Layout() {
 }
 
 void CustomButton::OnEnabledChanged() {
+  // TODO(bruthig): Is there any reason we are not calling
+  // Button::OnEnabledChanged() here?
   if (enabled() ? (state_ != STATE_DISABLED) : (state_ == STATE_DISABLED))
     return;
 
@@ -130,6 +132,7 @@ void CustomButton::OnEnabledChanged() {
     SetState(ShouldEnterHoveredState() ? STATE_HOVERED : STATE_NORMAL);
   else
     SetState(STATE_DISABLED);
+  UpdateInkDropHoverState();
 }
 
 const char* CustomButton::GetClassName() const {
@@ -193,12 +196,14 @@ void CustomButton::OnMouseCaptureLost() {
 void CustomButton::OnMouseEntered(const ui::MouseEvent& event) {
   if (state_ != STATE_DISABLED)
     SetState(STATE_HOVERED);
+  UpdateInkDropHoverState();
 }
 
 void CustomButton::OnMouseExited(const ui::MouseEvent& event) {
   // Starting a drag results in a MouseExited, we need to ignore it.
   if (state_ != STATE_DISABLED && !InDrag())
     SetState(STATE_NORMAL);
+  UpdateInkDropHoverState();

[sadrul, 2016/01/12 15:55:38]

Can ButtonInkDropDelegate take care of updating the hover state itself (other
than the enable-ness change case)?

[bruthig, 2016/01/12 16:27:17]

Done.

 }
 
 void CustomButton::OnMouseMoved(const ui::MouseEvent& event) {
@@ -352,6 +357,10 @@ gfx::Point CustomButton::CalculateInkDropCenter() const {
   return GetLocalBounds().CenterPoint();
 }
 
+bool CustomButton::ShouldShowInkDropHover() const {
+  return enabled() && IsMouseHovered() && !InDrag();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // CustomButton, protected:
 
@@ -408,6 +417,11 @@ bool CustomButton::ShouldEnterHoveredState() {
   return check_mouse_position && IsMouseHovered();
 }
 
+void CustomButton::UpdateInkDropHoverState() {
+  if (ink_drop_delegate_)
+    ink_drop_delegate_->SetHovered(ShouldShowInkDropHover());
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // CustomButton, View overrides (protected):