Plumb hasPreciseScrollingDeltas into ScrollGranularity for overflow scrolls.

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * 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.
@@ skipping 154 matching lines @@
     ~MaximumDurationTracker()
     {
         *m_maxDuration = max(*m_maxDuration, monotonicallyIncreasingTime() - m_start);
     }
 
 private:
     double* m_maxDuration;
     double m_start;
 };
 
-static inline ScrollGranularity wheelGranularityToScrollGranularity(unsigned deltaMode)
+static inline ScrollGranularity wheelGranularityToScrollGranularity(WheelEvent* event)
 {
-    switch (deltaMode) {
-    case WheelEvent::DOM_DELTA_PAGE:
+    unsigned deltaMode = event->deltaMode();
+    if (deltaMode == WheelEvent::DOM_DELTA_PAGE)
         return ScrollByPage;
-    case WheelEvent::DOM_DELTA_LINE:
+    if (deltaMode == WheelEvent::DOM_DELTA_LINE)
         return ScrollByLine;
-    case WheelEvent::DOM_DELTA_PIXEL:
-        return ScrollByPixel;
-    default:
-        return ScrollByPixel;
-    }
+    ASSERT(deltaMode == WheelEvent::DOM_DELTA_PIXEL);
+    return event->hasPreciseScrollingDeltas() ? ScrollByPrecisePixel : ScrollByPixel;
 }
 
 // Refetch the event target node if it is removed or currently is the shadow node inside an <input> element.
 // If a mouse event handler changes the input element type to one that has a widget associated,
 // we'd like to EventHandler::handleMousePressEvent to pass the event to the widget and thus the
 // event target node can't still be the shadow node.
 static inline bool shouldRefetchEventTarget(const MouseEventWithHitTestResults& mev)
 {
     Node* targetNode = mev.innerNode();
     if (!targetNode || !targetNode->parentNode())
@@ skipping 1840 matching lines @@
 void EventHandler::defaultWheelEventHandler(Node* startNode, WheelEvent* wheelEvent)
 {
     if (!startNode || !wheelEvent)
         return;
 
     // Ctrl + scrollwheel is reserved for triggering zoom in/out actions in Chromium.
     if (wheelEvent->ctrlKey())
         return;
 
     Node* stopNode = m_previousWheelScrolledNode.get();
-    ScrollGranularity granularity = wheelGranularityToScrollGranularity(wheelEvent->deltaMode());
+    ScrollGranularity granularity = wheelGranularityToScrollGranularity(wheelEvent);
 
     // Break up into two scrolls if we need to.  Diagonal movement on
     // a MacBook pro is an example of a 2-dimensional mouse wheel event (where both deltaX and deltaY can be set).
     if (scroll(ScrollRight, granularity, startNode, &stopNode, wheelEvent->deltaX(), roundedIntPoint(wheelEvent->absoluteLocation())))
         wheelEvent->setDefaultHandled();
 
     if (scroll(ScrollDown, granularity, startNode, &stopNode, wheelEvent->deltaY(), roundedIntPoint(wheelEvent->absoluteLocation())))
         wheelEvent->setDefaultHandled();
 
     if (!m_latchedWheelEventNode)
@@ skipping 1826 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink