Refactoring to make adding ink drop animations easier

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 8ae740a40f6907d11c074fed4613e1efb2b1f24a..2104c20b96388d8bb0051fcfe39d4e55b97446e8 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -39,6 +39,7 @@
 #include "ui/gfx/transform.h"
 #include "ui/native_theme/native_theme.h"
 #include "ui/views/accessibility/native_view_accessibility.h"
+#include "ui/views/animation/ink_drop_delegate.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
 #include "ui/views/context_menu_controller.h"
@@ -1015,6 +1016,9 @@ void View::OnTouchEvent(ui::TouchEvent* event) {
 }
 
 void View::OnGestureEvent(ui::GestureEvent* event) {
+  InkDropDelegate* ink_drop_delegate = GetInkDropDelegate();
+  if (ink_drop_delegate)
+    ink_drop_delegate->OnGestureEvent(event);
 }
 
 const ui::InputMethod* View::GetInputMethod() const {
@@ -1519,6 +1523,12 @@ void View::ReorderChildLayers(ui::Layer* parent_layer) {
   }
 }
 
+// Animations ----------------------------------------------------------------
+
+InkDropDelegate* View::GetInkDropDelegate() const {
+  return nullptr;
+}
+
 // Input -----------------------------------------------------------------------
 
 View::DragInfo* View::GetDragInfo() {