Refactoring to make adding ink drop animations easier

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 aafbf2d65a63aa32810d6da8d352f9bf1663f8af..ac9d0938d6a29b241a863cae997ec5d752d5bc20 100644
--- a/ui/views/controls/button/custom_button.cc
+++ b/ui/views/controls/button/custom_button.cc
@@ -10,6 +10,7 @@
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/gfx/animation/throb_animation.h"
 #include "ui/gfx/screen.h"
+#include "ui/views/animation/ink_drop_delegate.h"
 #include "ui/views/controls/button/blue_button.h"
 #include "ui/views/controls/button/checkbox.h"
 #include "ui/views/controls/button/image_button.h"
@@ -25,9 +26,33 @@
 
 namespace views {
 
+namespace {
+
+// A stub InkDropDelegate implementation that always exists and does nothing.
+// A real InkDropDelegate descendant can be returned by a View's descendant via
+// GetInkDropDelegate().
+class InkDropDelegateStub : public InkDropDelegate {
+ public:
+  InkDropDelegateStub() {}
+  ~InkDropDelegateStub() override {}
+
+  // InkDropDelegate:
+  void SetInkDropSize(int large_size,
+                      int large_corner_radius,
+                      int small_size,
+                      int small_corner_radius) override {}
+  void OnBoundsChanged() override {}
+  void OnAction(InkDropState state) override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(InkDropDelegateStub);
+};

[sadrul, 2015/11/25 22:38:58]

Still not a fan of this stub. I think we should still null-check (I don't think
there will be many places that does the nullcheck, so should be ok)

[varkha, 2015/11/26 00:05:46]

Done.

+
 // How long the hover animation takes if uninterrupted.
 static const int kHoverFadeDurationMs = 150;
 
+}  // namespace
+
 // static
 const char CustomButton::kViewClassName[] = "CustomButton";
 
@@ -284,6 +309,8 @@ void CustomButton::OnDragDone() {
   // (since disabled buttons may still be able to be dragged).
   if (state_ != STATE_DISABLED)
     SetState(STATE_NORMAL);
+  Button::OnDragDone();

[sadrul, 2015/11/25 22:38:58]

Is this still needed?

[varkha, 2015/11/26 00:05:47]

Done.

+  ink_drop_delegate_->OnAction(InkDropState::HIDDEN);
 }
 
 void CustomButton::GetAccessibleState(ui::AXViewState* state) {
@@ -324,6 +351,7 @@ void CustomButton::AnimationProgressed(const gfx::Animation* animation) {
 CustomButton::CustomButton(ButtonListener* listener)
     : Button(listener),
       state_(STATE_NORMAL),
+      ink_drop_delegate_(new InkDropDelegateStub),
       animate_on_state_change_(true),
       is_throbbing_(false),
       triggerable_event_flags_(ui::EF_LEFT_MOUSE_BUTTON),
@@ -374,6 +402,10 @@ bool CustomButton::ShouldEnterHoveredState() {
 ////////////////////////////////////////////////////////////////////////////////
 // CustomButton, View overrides (protected):
 
+void CustomButton::OnBoundsChanged(const gfx::Rect& previous_bounds) {
+  ink_drop_delegate_->OnBoundsChanged();
+}
+
 void CustomButton::ViewHierarchyChanged(
     const ViewHierarchyChangedDetails& details) {
   if (!details.is_add && state_ != STATE_DISABLED)