First pass at removing position:fixed.

sky/engine/core/rendering/PaintInvalidationState.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/rendering/PaintInvalidationState.h"
 
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderView.h"
@@ skipping 24 matching lines @@
 
 PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& next, RenderLayerModelObject& renderer, const RenderLayerModelObject& paintInvalidationContainer)
     : m_clipped(false)
     , m_cachedOffsetsEnabled(true)
     , m_forceCheckForPaintInvalidation(next.m_forceCheckForPaintInvalidation)
     , m_paintInvalidationContainer(paintInvalidationContainer)
     , m_renderer(renderer)
 {
     // FIXME: SVG could probably benefit from a stack-based optimization like html does. crbug.com/391054
     bool establishesPaintInvalidationContainer = &m_renderer == &m_paintInvalidationContainer;
-    bool fixed = m_renderer.style()->position() == FixedPosition;
 
     if (establishesPaintInvalidationContainer) {
         // When we hit a new paint invalidation container, we don't need to
         // continue forcing a check for paint invalidation because movement
         // from our parents will just move the whole invalidation container.
         m_forceCheckForPaintInvalidation = false;
     } else {
         if (!renderer.supportsPaintInvalidationStateCachedOffsets() || !next.m_cachedOffsetsEnabled) {
             m_cachedOffsetsEnabled = false;
         } else {
-            if (fixed) {
-                FloatPoint fixedOffset = m_renderer.localToContainerPoint(FloatPoint(), &m_paintInvalidationContainer, TraverseDocumentBoundaries);
-                m_paintOffset = LayoutSize(fixedOffset.x(), fixedOffset.y());
-            } else {
-                LayoutSize offset = m_renderer.isBox() ? toRenderBox(renderer).locationOffset() : LayoutSize();
-                m_paintOffset = next.m_paintOffset + offset;
-            }
+            LayoutSize offset = m_renderer.isBox() ? toRenderBox(renderer).locationOffset() : LayoutSize();
+            m_paintOffset = next.m_paintOffset + offset;
 
-            if (m_renderer.isOutOfFlowPositioned() && !fixed) {
+            if (m_renderer.isOutOfFlowPositioned()) {
                 if (RenderObject* container = m_renderer.container()) {
                     if (container->style()->hasInFlowPosition() && container->isRenderInline())
                         m_paintOffset += toRenderInline(container)->offsetForInFlowPositionedInline(toRenderBox(renderer));
                 }
             }
 
             if (m_renderer.style()->hasInFlowPosition() && renderer.hasLayer())
                 m_paintOffset += renderer.layer()->offsetForInFlowPosition();
         }
 
-        m_clipped = !fixed && next.m_clipped;
+        m_clipped = next.m_clipped;
         if (m_clipped)
             m_clipRect = next.m_clipRect;
     }
 
     applyClipIfNeeded(renderer);
 
     // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if present.
 }
 
 void PaintInvalidationState::applyClipIfNeeded(const RenderObject& renderer)
 {
     if (!renderer.hasOverflowClip())
         return;
 
     const RenderBox& box = toRenderBox(renderer);
     LayoutRect clipRect(toPoint(m_paintOffset), box.layer()->size());
     if (m_clipped) {
         m_clipRect.intersect(clipRect);
     } else {
         m_clipRect = clipRect;
         m_clipped = true;
     }
     m_paintOffset -= box.scrolledContentOffset();
 }
 
 } // namespace blink