Allow objects without scrollbars to be scrollable

Source/core/rendering/RenderLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 438 matching lines @@
     void scrollToYOffset(int y, ScrollOffsetClamping clamp = ScrollOffsetUnclamped) { scrollToOffset(IntSize(scrollXOffset(), y), clamp); }
 
     int scrollXOffset() const { return m_scrollOffset.width() + scrollOrigin().x(); }
     int scrollYOffset() const { return m_scrollOffset.height() + scrollOrigin().y(); }
     IntSize adjustedScrollOffset() const { return IntSize(scrollXOffset(), scrollYOffset()); }
 
     void scrollRectToVisible(const LayoutRect&, const ScrollAlignment& alignX, const ScrollAlignment& alignY);
 
     LayoutRect getRectToExpose(const LayoutRect& visibleRect, const LayoutRect& exposeRect, const ScrollAlignment& alignX, const ScrollAlignment& alignY);
 
-    bool scrollsOverflow() const;
-    bool hasScrollbars() const { return m_hBar || m_vBar; }
-    void setHasHorizontalScrollbar(bool);
-    void setHasVerticalScrollbar(bool);
-
-    PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
-    void destroyScrollbar(ScrollbarOrientation);
-
     bool hasHorizontalScrollbar() const { return horizontalScrollbar(); }
     bool hasVerticalScrollbar() const { return verticalScrollbar(); }
 
     // ScrollableArea overrides
     virtual Scrollbar* horizontalScrollbar() const { return m_hBar.get(); }
     virtual Scrollbar* verticalScrollbar() const { return m_vBar.get(); }
     virtual ScrollableArea* enclosingScrollableArea() const;
 
     int verticalScrollbarWidth(OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
     int horizontalScrollbarHeight(OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
 
-    bool hasOverflowControls() const;
     // isPointInResizeControl() is used for testing if a pointer/touch position is in the resize control
     // area.
     bool isPointInResizeControl(const IntPoint& absolutePoint, ResizerHitTestType resizerHitTestType) const;
     bool hitTestOverflowControls(HitTestResult&, const IntPoint& localPoint);
     IntSize offsetFromResizeCorner(const IntPoint& absolutePoint) const;
 
     void paintOverflowControls(GraphicsContext*, const IntPoint&, const IntRect& damageRect, bool paintingOverlayControls = false);
     void paintScrollCorner(GraphicsContext*, const IntPoint&, const IntRect& damageRect);
     void paintResizer(GraphicsContext*, const IntPoint&, const IntRect& damageRect);
 
@@ skipping 385 matching lines @@
 
     void setForceNeedsCompositedScrolling(ForceNeedsCompositedScrollingMode);
 
 private:
     enum CollectLayersBehavior {
         ForceLayerToStackingContainer,
         OverflowScrollCanBeStackingContainers,
         OnlyStackingContextsCanBeStackingContainers
     };
 
+    void setHasHorizontalScrollbar(bool);
+    void setHasVerticalScrollbar(bool);
+
+    PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
+    void destroyScrollbar(ScrollbarOrientation);
+
+    bool hasOverflowControls() const;
+
     void updateZOrderLists();
     void rebuildZOrderLists();
     // See the comment for collectLayers for information about the layerToForceAsStackingContainer parameter.
     void rebuildZOrderLists(OwnPtr<Vector<RenderLayer*> >&, OwnPtr<Vector<RenderLayer*> >&, const RenderLayer* layerToForceAsStackingContainer = 0, CollectLayersBehavior = OverflowScrollCanBeStackingContainers);
     void clearZOrderLists();
 
     void updateNormalFlowList();
 
     bool isStackingContext(const RenderStyle* style) const { return !style->hasAutoZIndex() || isRootLayer(); }
 
@@ skipping 179 matching lines @@
     virtual IntPoint maximumScrollPosition() const;
     virtual IntRect visibleContentRect(VisibleContentRectIncludesScrollbars) const;
     virtual int visibleHeight() const;
     virtual int visibleWidth() const;
     virtual IntSize contentsSize() const;
     virtual IntSize overhangAmount() const;
     virtual IntPoint lastKnownMousePosition() const;
     virtual bool shouldSuspendScrollAnimations() const;
     virtual bool scrollbarsCanBeActive() const;
     virtual IntRect scrollableAreaBoundingBox() const OVERRIDE;
+    virtual bool userInputScrollable(ScrollbarOrientation) const OVERRIDE;
+    virtual int pageStep(ScrollbarOrientation) const OVERRIDE;
 
     // Rectangle encompassing the scroll corner and resizer rect.
     IntRect scrollCornerAndResizerRect() const;
 
     void updateCompositingLayersAfterScroll();
 
     IntSize scrollbarOffset(const Scrollbar*) const;
     
     void updateResizerAreaSet();
     void updateScrollableAreaSet(bool hasOverflow);
@@ skipping 277 matching lines @@
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const WebCore::RenderLayer*);
 void showLayerTree(const WebCore::RenderObject*);
 #endif
 
 #endif // RenderLayer_h