Centered flood fill style ink drop ripples on mouse/touch points.

ui/events/event.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_EVENTS_EVENT_H_
 #define UI_EVENTS_EVENT_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 300 matching lines @@
 };
 
 class EVENTS_EXPORT CancelModeEvent : public Event {
  public:
   CancelModeEvent();
   ~CancelModeEvent() override;
 };
 
 class EVENTS_EXPORT LocatedEvent : public Event {
  public:
+  // Convenience function that casts |event| to a LocatedEvent if it is one,
+  // otherwise returns null.
+  static const ui::LocatedEvent* FromIfValid(const ui::Event* event) {
+    return event && event->IsLocatedEvent() ? event->AsLocatedEvent() : nullptr;
+  }
+
   ~LocatedEvent() override;
 
   float x() const { return location_.x(); }
   float y() const { return location_.y(); }
   void set_location(const gfx::Point& location) {
     location_ = gfx::PointF(location);
   }
   void set_location_f(const gfx::PointF& location) { location_ = location; }
   gfx::Point location() const { return gfx::ToFlooredPoint(location_); }
   const gfx::PointF& location_f() const { return location_; }
@@ skipping 690 matching lines @@
   // dispatched. This field gets a non-zero value only for gestures that are
   // released through TouchDispositionGestureFilter::SendGesture. The gesture
   // events that aren't fired directly in response to processing a touch-event
   // (e.g. timer fired ones), this id is zero. See crbug.com/618738.
   uint32_t unique_touch_event_id_;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_H_