Gesture event hit test refactoring and reduction

Source/platform/PlatformGestureEvent.h

 /*
  * Copyright (C) 2011 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 31 matching lines @@
     {
         memset(&m_data, 0, sizeof(m_data));
     }
 
     PlatformGestureEvent(Type type, const IntPoint& position, const IntPoint& globalPosition, const IntSize& area, double timestamp, bool shiftKey, bool ctrlKey, bool altKey, bool metaKey, float deltaX, float deltaY, float velocityX, float velocityY)
         : PlatformEvent(type, shiftKey, ctrlKey, altKey, metaKey, timestamp)
         , m_position(position)
         , m_globalPosition(globalPosition)
         , m_area(area)
     {
-        ASSERT(type == PlatformEvent::GestureScrollBegin
+        memset(&m_data, 0, sizeof(m_data));
+        if (type == PlatformEvent::GestureScrollBegin
             || type == PlatformEvent::GestureScrollEnd
             || type == PlatformEvent::GestureScrollUpdate
-            || type == PlatformEvent::GestureScrollUpdateWithoutPropagation);
-        memset(&m_data, 0, sizeof(m_data));
-        m_data.m_scrollUpdate.m_deltaX = deltaX;
-        m_data.m_scrollUpdate.m_deltaY = deltaY;
-        m_data.m_scrollUpdate.m_velocityX = velocityX;
-        m_data.m_scrollUpdate.m_velocityY = velocityY;
+            || type == PlatformEvent::GestureScrollUpdateWithoutPropagation) {
+            m_data.m_scrollUpdate.m_deltaX = deltaX;
+            m_data.m_scrollUpdate.m_deltaY = deltaY;
+            m_data.m_scrollUpdate.m_velocityX = velocityX;
+            m_data.m_scrollUpdate.m_velocityY = velocityY;
+        }
     }
 
     const IntPoint& position() const { return m_position; } // PlatformWindow coordinates.
     const IntPoint& globalPosition() const { return m_globalPosition; } // Screen coordinates.
 
     const IntSize& area() const { return m_area; }
 
     float deltaX() const
     {
         ASSERT(m_type == PlatformEvent::GestureScrollUpdate
@@ skipping 27 matching lines @@
             || m_type == PlatformEvent::GestureScrollUpdateWithoutPropagation);
         return m_data.m_scrollUpdate.m_velocityY;
     }
 
     float scale() const
     {
         ASSERT(m_type == PlatformEvent::GesturePinchUpdate);
         return m_data.m_pinchUpdate.m_scale;
     }
 
+    void applyTouchAdjustment(const IntPoint& adjustedPosition)
+    {
+        // Update the window-relative position of the event so that the node that was
+        // ultimately hit is under this point (i.e. elementFromPoint for the client
+        // co-ordinates in a 'click' event should yield the target). The global
+        // position is intentionally left unmodified because it's intended to reflect
+        // raw co-ordinates unrelated to any content.
+        m_position = adjustedPosition;
+    }
+
+    bool isScrollEvent() const
+    {
+        switch (m_type) {
+        case GestureScrollBegin:
+        case GestureScrollEnd:
+        case GestureScrollUpdate:
+        case GestureScrollUpdateWithoutPropagation:
+        case GestureFlingStart:
+            return true;
+        default:
+            return false;

[esprehn, 2014/06/27 08:33:58]

Can you list them all instead? Then when someone adds a new one they can't
forget to update this switch.

[Rick Byers, 2014/06/27 15:38:24]

Done.

+        }
+    }
+
 protected:
     IntPoint m_position;
     IntPoint m_globalPosition;
     IntSize m_area;
 
     union {
         struct {
             int m_tapCount;
         } m_tap;
 
         struct {
             float m_deltaX;
             float m_deltaY;
             float m_velocityX;
             float m_velocityY;
         } m_scrollUpdate;
 
         struct {
             float m_scale;
         } m_pinchUpdate;
     } m_data;
 };
 
 } // namespace WebCore
 
 #endif // PlatformGestureEvent_h