Ignore overflow clip on root layer if HitTestRequest::IgnoreClipping is set.

Source/core/paint/DeprecatedPaintLayerClipper.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 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 216 matching lines @@
     LayoutPoint offset;
     if (offsetFromRoot)
         offset = *offsetFromRoot;
     else
         m_layoutObject.layer()->convertToLayerCoords(context.rootLayer, offset);
     layerBounds = LayoutRect(offset, LayoutSize(m_layoutObject.layer()->size()));
 
     // Update the clip rects that will be passed to child layers.
     if (m_layoutObject.hasOverflowClip()) {
         // This layer establishes a clip of some kind.
-        if (!isClippingRoot || context.respectOverflowClip == RespectOverflowClip) {
+        if (shouldRespectOverflowClip(context)) {
             foregroundRect.intersect(toLayoutBox(m_layoutObject).overflowClipRect(offset, context.scrollbarRelevancy));
             if (m_layoutObject.style()->hasBorderRadius())
                 foregroundRect.setHasRadius(true);
         }
 
         // If we establish an overflow clip at all, then go ahead and make sure our background
         // rect is intersected with our layer's bounds including our visual overflow,
         // since any visual overflow like box-shadow or border-outset is not clipped by overflow:auto/hidden.
         if (toLayoutBox(m_layoutObject).hasVisualOverflow()) {
             // FIXME: Perhaps we should be propagating the borderbox as the clip rect for children, even though
             //        we may need to inflate our clip specifically for shadows or outsets.
             // FIXME: Does not do the right thing with columns yet, since we don't yet factor in the
             // individual column boxes as overflow.
             LayoutRect layerBoundsWithVisualOverflow = toLayoutBox(m_layoutObject).visualOverflowRect();
             toLayoutBox(m_layoutObject).flipForWritingMode(layerBoundsWithVisualOverflow); // DeprecatedPaintLayer are in physical coordinates, so the overflow has to be flipped.
             layerBoundsWithVisualOverflow.moveBy(offset);
-            if (!isClippingRoot || context.respectOverflowClip == RespectOverflowClip)
+            if (shouldRespectOverflowClip(context))
                 backgroundRect.intersect(layerBoundsWithVisualOverflow);
         } else {
             LayoutRect bounds = toLayoutBox(m_layoutObject).borderBoxRect();
             bounds.moveBy(offset);
-            if (!isClippingRoot || context.respectOverflowClip == RespectOverflowClip)
+            if (shouldRespectOverflowClip(context))
                 backgroundRect.intersect(bounds);
         }
     }
 
     // CSS clip (different than clipping due to overflow) can clip to any box, even if it falls outside of the border box.
     if (m_layoutObject.hasClip()) {
         // Clip applies to *us* as well, so go ahead and update the damageRect.
         LayoutRect newPosClip = toLayoutBox(m_layoutObject).clipRect(offset);
         backgroundRect.intersect(newPosClip);
         foregroundRect.intersect(newPosClip);
@@ skipping 23 matching lines @@
             clipRects = *parentLayer->clipper().cachedClipRects(context);
         } else {
             parentLayer->clipper().calculateClipRects(context, clipRects);
         }
     } else {
         clipRects.reset(LayoutRect(LayoutRect::infiniteIntRect()));
     }
 
     adjustClipRectsForChildren(m_layoutObject, clipRects);
 
-    if ((m_layoutObject.hasOverflowClip() && (context.respectOverflowClip == RespectOverflowClip || !isClippingRoot)) || m_layoutObject.hasClip()) {
+    if ((m_layoutObject.hasOverflowClip() && shouldRespectOverflowClip(context)) || m_layoutObject.hasClip()) {
         // This offset cannot use convertToLayerCoords, because sometimes our rootLayer may be across
         // some transformed layer boundary, for example, in the DeprecatedPaintLayerCompositor overlapMap, where
         // clipRects are needed in view space.
         applyClipRects(context, m_layoutObject, roundedLayoutPoint(m_layoutObject.localToContainerPoint(FloatPoint(), context.rootLayer->layoutObject())), clipRects);
     }
 }
 
 static ClipRect backgroundClipRectForPosition(const ClipRects& parentRects, EPosition position)
 {
     if (position == FixedPosition)
@@ skipping 50 matching lines @@
         current = current->compositingContainer();
         ASSERT(current);
         if (current->transform() || current->isPaintInvalidationContainer())
             return const_cast<DeprecatedPaintLayer*>(current);
     }
 
     ASSERT_NOT_REACHED();
     return 0;
 }
 
+bool DeprecatedPaintLayerClipper::shouldRespectOverflowClip(const ClipRectsContext& context) const
+{
+    DeprecatedPaintLayer* layer = m_layoutObject.layer();
+    if (layer != context.rootLayer)
+        return true;
+
+    if (context.respectOverflowClip == IgnoreOverflowClip)
+        return false;
+
+    if (layer->isRootLayer() && context.respectOverflowClipForViewport == IgnoreOverflowClip)
+        return false;
+
+    return true;
+}
+
 } // namespace blink