Remove a bit more position:fixed plumbing.

sky/engine/core/rendering/RenderBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 1153 matching lines @@
         // LayoutState needs this deliberate scope to pop before paint invalidation.
         LayoutState state(*this, locationOffset());
 
         if (needsPositionedMovementLayout() && !tryLayoutDoingPositionedMovementOnly())
             return false;
 
         // Lay out positioned descendants or objects that just need to recompute overflow.
         if (needsSimplifiedNormalFlowLayout())
             simplifiedNormalFlowLayout();
 
-        // Lay out our positioned objects if our positioned child bit is set.
-        // Also, if an absolute position element inside a relative positioned container moves, and the absolute element has a fixed position
-        // child, neither the fixed element nor its container learn of the movement since posChildNeedsLayout() is only marked as far as the
-        // relative positioned container. So if we can have fixed pos objects in our positioned objects list check if any of them
-        // are statically positioned and thus need to move with their absolute ancestors.
-        bool canContainFixedPosObjects = canContainFixedPositionObjects();
-        if (posChildNeedsLayout() || needsPositionedMovementLayout() || canContainFixedPosObjects)
-            layoutPositionedObjects(false, needsPositionedMovementLayout() ? ForcedLayoutAfterContainingBlockMoved : (!posChildNeedsLayout() && canContainFixedPosObjects ? LayoutOnlyFixedPositionedObjects : DefaultLayout));
+        if (posChildNeedsLayout() || needsPositionedMovementLayout())
+            layoutPositionedObjects(false, needsPositionedMovementLayout() ? ForcedLayoutAfterContainingBlockMoved : DefaultLayout);
 
         // Recompute our overflow information.
         // FIXME: We could do better here by computing a temporary overflow object from layoutPositionedObjects and only
         // updating our overflow if we either used to have overflow or if the new temporary object has overflow.
         // For now just always recompute overflow. This is no worse performance-wise than the old code that called rightmostPosition and
         // lowestPosition on every relayout so it's not a regression.
         // computeOverflow expects the bottom edge before we clamp our height. Since this information isn't available during
         // simplifiedLayout, we cache the value in m_overflow.
         LayoutUnit oldClientAfterEdge = hasRenderOverflow() ? m_overflow->layoutClientAfterEdge() : clientLogicalBottom();
         computeOverflow(oldClientAfterEdge, true);
     }
 
     updateLayerTransformAfterLayout();
 
     updateScrollInfoAfterLayout();
 
     clearNeedsLayout();
     return true;
 }
 
-void RenderBlock::markFixedPositionObjectForLayoutIfNeeded(RenderObject* child, SubtreeLayoutScope& layoutScope)
-{
-    // FIXME(sky): Remove
-}
-
 LayoutUnit RenderBlock::marginIntrinsicLogicalWidthForChild(RenderBox* child) const
 {
     // A margin has three types: fixed, percentage, and auto (variable).
     // Auto and percentage margins become 0 when computing min/max width.
     // Fixed margins can be added in as is.
     Length marginLeft = child->style()->marginStartUsing(style());
     Length marginRight = child->style()->marginEndUsing(style());
     LayoutUnit margin = 0;
     if (marginLeft.isFixed())
         margin += marginLeft.value();
@@ skipping 10 matching lines @@
 
     RenderBox* r;
     TrackedRendererListHashSet::iterator end = positionedDescendants->end();
     for (TrackedRendererListHashSet::iterator it = positionedDescendants->begin(); it != end; ++it) {
         r = *it;
 
         // FIXME: this should only be set from clearNeedsLayout crbug.com/361250
         r->setLayoutDidGetCalled(true);
 
         SubtreeLayoutScope layoutScope(*r);
-        // A fixed position element with an absolute positioned ancestor has no way of knowing if the latter has changed position. So
-        // if this is a fixed position element, mark it for layout if it has an abspos ancestor and needs to move with that ancestor, i.e.
-        // it has static position.
-        markFixedPositionObjectForLayoutIfNeeded(r, layoutScope);
-        if (info == LayoutOnlyFixedPositionedObjects) {
-            r->layoutIfNeeded();
-            continue;
-        }
 
         // When a non-positioned block element moves, it may have positioned children that are implicitly positioned relative to the
         // non-positioned block.  Rather than trying to detect all of these movement cases, we just always lay out positioned
         // objects that are positioned implicitly like this.  Such objects are rare, and so in typical DHTML menu usage (where everything is
         // positioned explicitly) this should not incur a performance penalty.
         if (relayoutChildren || (r->style()->hasStaticBlockPosition(isHorizontalWritingMode()) && r->parent() != this))
             layoutScope.setChildNeedsLayout(r);
 
         // If relayoutChildren is set and the child has percentage padding or an embedded content box, we also need to invalidate the childs pref widths.
         if (relayoutChildren && r->needsPreferredWidthsRecalculation())
@@ skipping 1967 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink