Gesture event hit test refactoring and reduction

Source/platform/PlatformGestureEvent.h

Index: Source/platform/PlatformGestureEvent.h
diff --git a/Source/platform/PlatformGestureEvent.h b/Source/platform/PlatformGestureEvent.h
index 254224640898f9ccbc5dfc7b613207f82a226dcc..f407d9b93c88328f87eb6ccc881966ea72ac8c5f 100644
--- a/Source/platform/PlatformGestureEvent.h
+++ b/Source/platform/PlatformGestureEvent.h
@@ -49,15 +49,16 @@ public:
         , 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.
@@ -105,6 +106,43 @@ public:
         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:
+        case GesturePinchBegin:
+        case GesturePinchEnd:
+        case GesturePinchUpdate:

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

Note that pinch events are really logical extensions of scroll events and have
the same conceptual hit-test behavior, so it makes sense to treat them the same.
 But for the most part they're ignored by blink and handled directly by CC, so
the difference isn't too relevant here.

+            return true;
+        case GestureTap:
+        case GestureTapUnconfirmed:
+        case GestureTapDown:
+        case GestureShowPress:
+        case GestureTapDownCancel:
+        case GestureTwoFingerTap:
+        case GestureLongPress:
+        case GestureLongTap:
+            return false;
+        default:
+            ASSERT_NOT_REACHED();
+            return false;
+        }
+    }
+
 protected:
     IntPoint m_position;
     IntPoint m_globalPosition;