Use reference for FillLayer if possible

Source/core/rendering/RenderObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 886 matching lines @@
             return true;
     } else if (img->usesImageContainerSize()) {
         return true;
     }
 
     return false;
 }
 
 bool RenderObject::mustInvalidateBackgroundOrBorderPaintOnWidthChange() const
 {
-    if (hasMask() && mustInvalidateFillLayersPaintOnWidthChange(*style()->maskLayers()))
+    if (hasMask() && mustInvalidateFillLayersPaintOnWidthChange(style()->maskLayers()))
         return true;
 
     // If we don't have a background/border/mask, then nothing to do.
     if (!hasBoxDecorationBackground())
         return false;
 
-    if (mustInvalidateFillLayersPaintOnWidthChange(*style()->backgroundLayers()))
+    if (mustInvalidateFillLayersPaintOnWidthChange(style()->backgroundLayers()))
         return true;
 
     // Our fill layers are ok. Let's check border.
     if (style()->hasBorder() && canRenderBorderImage())
         return true;
 
     return false;
 }
 
 bool RenderObject::mustInvalidateBackgroundOrBorderPaintOnHeightChange() const
 {
-    if (hasMask() && mustInvalidateFillLayersPaintOnHeightChange(*style()->maskLayers()))
+    if (hasMask() && mustInvalidateFillLayersPaintOnHeightChange(style()->maskLayers()))
         return true;
 
     // If we don't have a background/border/mask, then nothing to do.
     if (!hasBoxDecorationBackground())
         return false;
 
-    if (mustInvalidateFillLayersPaintOnHeightChange(*style()->backgroundLayers()))
+    if (mustInvalidateFillLayersPaintOnHeightChange(style()->backgroundLayers()))
         return true;
 
     // Our fill layers are ok.  Let's check border.
     if (style()->hasBorder() && canRenderBorderImage())
         return true;
 
     return false;
 }
 
 void RenderObject::drawLineForBoxSide(GraphicsContext* graphicsContext, int x1, int y1, int x2, int y2,
@@ skipping 1070 matching lines @@
     if (m_style)
         diff = m_style->visualInvalidationDiff(*style);
 
     diff = adjustStyleDifference(diff);
 
     styleWillChange(diff, *style);
 
     RefPtr<RenderStyle> oldStyle = m_style.release();
     setStyleInternal(style);
 
-    updateFillImages(oldStyle ? oldStyle->backgroundLayers() : 0, m_style ? m_style->backgroundLayers() : 0);
-    updateFillImages(oldStyle ? oldStyle->maskLayers() : 0, m_style ? m_style->maskLayers() : 0);
+    updateFillImages(oldStyle ? &oldStyle->backgroundLayers() : 0, m_style->backgroundLayers());
+    updateFillImages(oldStyle ? &oldStyle->maskLayers() : 0, m_style->maskLayers());
 
-    updateImage(oldStyle ? oldStyle->borderImage().image() : 0, m_style ? m_style->borderImage().image() : 0);
-    updateImage(oldStyle ? oldStyle->maskBoxImage().image() : 0, m_style ? m_style->maskBoxImage().image() : 0);
+    updateImage(oldStyle ? oldStyle->borderImage().image() : 0, m_style->borderImage().image());
+    updateImage(oldStyle ? oldStyle->maskBoxImage().image() : 0, m_style->maskBoxImage().image());
 
-    updateShapeImage(oldStyle ? oldStyle->shapeOutside() : 0, m_style ? m_style->shapeOutside() : 0);
+    updateShapeImage(oldStyle ? oldStyle->shapeOutside() : 0, m_style->shapeOutside());
 
     bool doesNotNeedLayout = !m_parent || isText();
 
     styleDidChange(diff, oldStyle.get());
 
     // FIXME: |this| might be destroyed here. This can currently happen for a RenderTextFragment when
     // its first-letter block gets an update in RenderTextFragment::styleDidChange. For RenderTextFragment(s),
     // we will safely bail out with the doesNotNeedLayout flag. We might want to broaden this condition
     // in the future as we move renderer changes out of layout and into style changes.
     if (doesNotNeedLayout)
@@ skipping 205 matching lines @@
 
         // Preserve the position style of anonymous block continuations as they can have relative position when
         // they contain block descendants of relative positioned inlines.
         if (child->isRelPositioned() && toRenderBlock(child)->isAnonymousBlockContinuation())
             newStyle->setPosition(child->style()->position());
 
         child->setStyle(newStyle.release());
     }
 }
 
-void RenderObject::updateFillImages(const FillLayer* oldLayers, const FillLayer* newLayers)
+void RenderObject::updateFillImages(const FillLayer* oldLayers, const FillLayer& newLayers)
 {
     // Optimize the common case
-    if (oldLayers && !oldLayers->next() && newLayers && !newLayers->next() && (oldLayers->image() == newLayers->image()))
+    if (oldLayers && !oldLayers->next() && !newLayers.next() && (oldLayers->image() == newLayers.image()))
         return;
 
     // Go through the new layers and addClients first, to avoid removing all clients of an image.
-    for (const FillLayer* currNew = newLayers; currNew; currNew = currNew->next()) {
+    for (const FillLayer* currNew = &newLayers; currNew; currNew = currNew->next()) {
         if (currNew->image())
             currNew->image()->addClient(this);
     }
 
     for (const FillLayer* currOld = oldLayers; currOld; currOld = currOld->next()) {
         if (currOld->image())
             currOld->image()->removeClient(this);
     }
 }
 
@@ skipping 536 matching lines @@
     if (!shapeValue)
         return;
     if (StyleImage* shapeImage = shapeValue->image())
         shapeImage->removeClient(this);
 }
 
 void RenderObject::postDestroy()
 {
     // It seems ugly that this is not in willBeDestroyed().
     if (m_style) {
-        for (const FillLayer* bgLayer = m_style->backgroundLayers(); bgLayer; bgLayer = bgLayer->next()) {
+        for (const FillLayer* bgLayer = &m_style->backgroundLayers(); bgLayer; bgLayer = bgLayer->next()) {
             if (StyleImage* backgroundImage = bgLayer->image())
                 backgroundImage->removeClient(this);
         }
 
-        for (const FillLayer* maskLayer = m_style->maskLayers(); maskLayer; maskLayer = maskLayer->next()) {
+        for (const FillLayer* maskLayer = &m_style->maskLayers(); maskLayer; maskLayer = maskLayer->next()) {
             if (StyleImage* maskImage = maskLayer->image())
                 maskImage->removeClient(this);
         }
 
         if (StyleImage* borderImage = m_style->borderImage().image())
             borderImage->removeClient(this);
 
         if (StyleImage* maskBoxImage = m_style->maskBoxImage().image())
             maskBoxImage->removeClient(this);
 
@@ skipping 611 matching lines @@
 {
     if (object1) {
         const WebCore::RenderObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showRenderTreeAndMark(object1, "*", object2, "-", 0);
     }
 }
 
 #endif