Remove special wheel handling path from ScrollableArea

Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 286 matching lines @@
     else if (behaviorString == "instant")
         behavior = ScrollBehaviorInstant;
     else if (behaviorString == "smooth")
         behavior = ScrollBehaviorSmooth;
     else
         return false;
 
     return true;
 }
 
-ScrollResult ScrollableArea::handleWheel(const PlatformWheelEvent& wheelEvent)
-{
-    // Wheel events which do not scroll are used to trigger zooming.
-    if (!wheelEvent.canScroll())
-        return ScrollResult();
-
-    cancelProgrammaticScrollAnimation();
-    return scrollAnimator()->handleWheelEvent(wheelEvent);
-}
-
 // NOTE: Only called from Internals for testing.
 void ScrollableArea::setScrollOffsetFromInternals(const IntPoint& offset)
 {
     scrollPositionChanged(DoublePoint(offset), ProgrammaticScroll);
 }
 
 void ScrollableArea::willStartLiveResize()
 {
     if (m_inLiveResize)
         return;
@@ skipping 242 matching lines @@
 IntPoint ScrollableArea::clampScrollPosition(const IntPoint& scrollPosition) const
 {
     return scrollPosition.shrunkTo(maximumScrollPosition()).expandedTo(minimumScrollPosition());
 }
 
 DoublePoint ScrollableArea::clampScrollPosition(const DoublePoint& scrollPosition) const
 {
     return scrollPosition.shrunkTo(maximumScrollPositionDouble()).expandedTo(minimumScrollPositionDouble());
 }
 
-
 int ScrollableArea::lineStep(ScrollbarOrientation) const
 {
     return pixelsPerLineStep();
 }
 
 int ScrollableArea::pageStep(ScrollbarOrientation orientation) const
 {
-    int length = (orientation == HorizontalScrollbar) ? visibleWidth() : visibleHeight();
+    IntRect visibleRect = visibleContentRect(IncludeScrollbars);
+    int length = (orientation == HorizontalScrollbar) ? visibleRect.width() : visibleRect.height();
     int minPageStep = static_cast<float>(length) * minFractionToStepWhenPaging();
     int pageStep = std::max(minPageStep, length - maxOverlapBetweenPages());
 
     return std::max(pageStep, 1);
 }
 
 int ScrollableArea::documentStep(ScrollbarOrientation orientation) const
 {
     return scrollSize(orientation);
 }
@@ skipping 12 matching lines @@
         verticalScrollbarWidth = !verticalBar->isOverlayScrollbar() ? verticalBar->width() : 0;
     if (Scrollbar* horizontalBar = horizontalScrollbar())
         horizontalScrollbarHeight = !horizontalBar->isOverlayScrollbar() ? horizontalBar->height() : 0;
 
     return IntSize(std::max(0, size.width() - verticalScrollbarWidth),
         std::max(0, size.height() - horizontalScrollbarHeight));
 
 }
 
 } // namespace blink